JPH0776771A - Tungsten sputtering target - Google Patents
Tungsten sputtering targetInfo
- Publication number
- JPH0776771A JPH0776771A JP24603193A JP24603193A JPH0776771A JP H0776771 A JPH0776771 A JP H0776771A JP 24603193 A JP24603193 A JP 24603193A JP 24603193 A JP24603193 A JP 24603193A JP H0776771 A JPH0776771 A JP H0776771A
- Authority
- JP
- Japan
- Prior art keywords
- tungsten
- less
- target
- sputtering target
- ppm
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 title claims abstract description 58
- 229910052721 tungsten Inorganic materials 0.000 title claims abstract description 44
- 239000010937 tungsten Substances 0.000 title claims abstract description 44
- 238000005477 sputtering target Methods 0.000 title claims description 16
- 239000002245 particle Substances 0.000 claims abstract description 20
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 18
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 18
- 239000001257 hydrogen Substances 0.000 claims abstract description 18
- 229910052776 Thorium Inorganic materials 0.000 claims abstract description 11
- 229910052770 Uranium Inorganic materials 0.000 claims abstract description 10
- 239000012535 impurity Substances 0.000 claims abstract description 9
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 13
- 229910052760 oxygen Inorganic materials 0.000 claims description 13
- 239000001301 oxygen Substances 0.000 claims description 13
- 238000004519 manufacturing process Methods 0.000 claims description 11
- 238000000034 method Methods 0.000 claims description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 9
- 229910052799 carbon Inorganic materials 0.000 claims description 9
- 238000004544 sputter deposition Methods 0.000 abstract description 7
- 238000000746 purification Methods 0.000 abstract description 5
- 238000005098 hot rolling Methods 0.000 abstract description 2
- 239000010408 film Substances 0.000 description 17
- 239000013078 crystal Substances 0.000 description 16
- 239000007864 aqueous solution Substances 0.000 description 11
- 238000010438 heat treatment Methods 0.000 description 9
- 239000002994 raw material Substances 0.000 description 9
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 6
- XAYGUHUYDMLJJV-UHFFFAOYSA-Z decaazanium;dioxido(dioxo)tungsten;hydron;trioxotungsten Chemical compound [H+].[H+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O XAYGUHUYDMLJJV-UHFFFAOYSA-Z 0.000 description 6
- 238000005096 rolling process Methods 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 239000000758 substrate Substances 0.000 description 4
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 3
- 239000004484 Briquette Substances 0.000 description 3
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 3
- 239000013522 chelant Substances 0.000 description 3
- 229920001429 chelating resin Polymers 0.000 description 3
- SFZULDYEOVSIKM-UHFFFAOYSA-N chembl321317 Chemical compound C1=CC(C(=N)NO)=CC=C1C1=CC=C(C=2C=CC(=CC=2)C(=N)NO)O1 SFZULDYEOVSIKM-UHFFFAOYSA-N 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000012452 mother liquor Substances 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 230000002285 radioactive effect Effects 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- 239000011347 resin Substances 0.000 description 3
- 150000003658 tungsten compounds Chemical class 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- CMPGARWFYBADJI-UHFFFAOYSA-L tungstic acid Chemical compound O[W](O)(=O)=O CMPGARWFYBADJI-UHFFFAOYSA-L 0.000 description 2
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Natural products N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 1
- 239000003729 cation exchange resin Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000013077 target material Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Landscapes
- Physical Vapour Deposition (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、タングステンスパッタ
リングターゲット及びその製造方法に関するものであ
り、特には高密度、更には高密度・高純度タングステン
スパッタリングターゲット及びその製造方法に関するも
のである。本発明のターゲットにより生成されたタング
ステン膜は、パーティクル低下による信頼性向上、ソフ
トエラー低減による信頼性向上、膜特性改善による高性
能化等の利点があり、より一層高集積化した微細幅のタ
ングステン膜として有効である。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tungsten sputtering target and a method for producing the same, and more particularly to a high density, high density and high purity tungsten sputtering target and a method for producing the same. The tungsten film produced by the target of the present invention has advantages such as improved reliability due to particle reduction, improved reliability due to soft error reduction, and higher performance due to improved film characteristics. Effective as a film.
【０００２】[0002]
【従来の技術】スパッタリングターゲットは、スパッタ
リングにより各種の半導体デバイスの電極、ゲート、配
線、素子、絶縁膜、保護膜等を基板上に形成するための
スパッタリング源となる、通常は円盤状の板である。加
速された粒子がターゲット表面に衝突するとき運動量の
交換によりターゲットを構成する原子が空間に放出され
て対向する基板上に堆積する。近時、タングステン製の
電極、配線等が使用されることが多いが、タングステン
製の電極、配線等のタングステン膜はタングステンター
ゲットを用いたスパッタリング法により好適に形成され
る。2. Description of the Related Art Sputtering targets are usually disk-shaped plates that serve as sputtering sources for forming electrodes, gates, wirings, elements, insulating films, protective films, etc. of various semiconductor devices on a substrate by sputtering. is there. When the accelerated particles collide with the target surface, the atoms constituting the target are released into space by the exchange of momentum and are deposited on the facing substrate. Recently, tungsten electrodes and wirings are often used, but tungsten films such as tungsten electrodes and wirings are preferably formed by a sputtering method using a tungsten target.
【０００３】ターゲットのスパッタリングにおいて重要
な問題の一つは、パーティクルが発生してスパッタ膜を
汚染し、その膜特性が低下することである。この「パー
ティクル」とは、スパッタリングによる薄膜形成時に装
置内を飛散する粒子がクラスター化して基板上に堆積し
たものを云うのであるが、このクラスター化粒子は直径
が数μｍ程度にまで大きくなるものが多いので、これが
基板上に堆積すると、例えばＬＳＩの場合は配線の短絡
或いは逆に断線を引き起こす等の問題を生じ、不良率増
大の原因となる。これらのパーティクルはターゲットか
ら放出される粒子に起因する。One of the important problems in sputtering a target is that particles are generated and the sputtered film is contaminated, and the film characteristics are deteriorated. The term "particles" refers to particles that are scattered in the apparatus during the formation of a thin film by sputtering and are deposited on the substrate in clusters. The clustered particles are those whose diameter increases up to several μm. Since many of them are deposited on the substrate, problems such as short-circuiting of wiring or conversely disconnection occur in the case of LSI, for example, which causes an increase in defective rate. These particles are due to the particles emitted from the target.
【０００４】スパッタリング法の場合特にターゲット材
料の性状が素子の電極、配線等の特性を決定づける重要
な要因となる。タングステンターゲットに関しては、そ
の密度、結晶粒等と関連してこれまで幾つかの提唱がな
されている。例えば、特開平５−９３２６７号は、Ｃ：
５０ｐｐｍ以下、０：３０ｐｐｍ以下、密度：９７％以
上、結晶粒がほぼ一定方向につぶれたことを特徴とする
タングステンターゲットを提唱している。特開平３−１
５０３５６号は、密度９９％以上で平均粒径が１０μｍ
以下のタングステンターゲットを提唱している。特開平
４−１６０１０４号は、ＨＩＰにより密度９８％以上の
タングステンターゲットを製造する方法を記載してい
る。In the case of the sputtering method, the properties of the target material are particularly important factors that determine the characteristics of the electrodes and wiring of the device. Regarding the tungsten target, some proposals have been made so far in relation to its density, crystal grains, and the like. For example, JP-A-5-93267 discloses C:
A tungsten target is proposed, which is characterized by 50 ppm or less, 0:30 ppm or less, density: 97% or more, and crystal grains crushed in a substantially constant direction. Japanese Patent Laid-Open No. 3-1
No. 50356 has a density of 99% or more and an average particle size of 10 μm.
The following tungsten targets are proposed. Japanese Patent Laid-Open No. 4-160104 describes a method of manufacturing a tungsten target having a density of 98% or more by HIP.
【０００５】[0005]
【発明が解決しようとする課題】半導体デバイスの近時
の急速な高精細化及び高集積化によりまた信頼性の一層
の向上への要求により、タングステン配線、電極等のタ
ングステン膜に関して、パーティクル低下による信頼性
向上、ソフトエラー低減による信頼性向上、比抵抗の低
減化による高性能化等の問題が改めて認識されるように
なっている。上に挙げたようなタングステンターゲット
では、こうした要求を充分に満足させることはできな
い。Due to the recent rapid high definition and high integration of semiconductor devices and the demand for further improvement of reliability, particles of tungsten films such as tungsten wiring and electrodes are reduced. Problems such as improvement in reliability, improvement in reliability by reducing soft errors, and improvement in performance by reducing specific resistance have been recognized again. The above-mentioned tungsten targets cannot fully satisfy these requirements.
【０００６】本発明の課題は、膜の生成に際して、パー
ティクルの低下、ソフトエラーの低減及び比抵抗の低減
という要求の少なくとも一つ、好ましくはこれら要求を
同時に満足するタングステンターゲットを開発すること
である。An object of the present invention is to develop a tungsten target which satisfies at least one of the requirements of particle reduction, soft error reduction and specific resistance reduction, preferably at the same time, when forming a film. .
【０００７】[0007]
【課題を解決するための手段】本発明者の研究の結果、
パーティクルを従来より一層低下させるためには、密度
規定を従来より一層厳密に規定して９９．５％以上の密
度を実現することが必要であることが判明した。ソフト
エラーの低減及び比抵抗の低減という要求を満足させる
ためには、Ｕ、Ｔｈ等放射性元素並びに炭素及び酸素そ
の他の不純物の含有量を低減することが必要である。本
発明者は、タングステン粉末の焼結体を水素雰囲気中で
２０００℃以上に加熱して圧延することにより相対密度
９９．５％以上の高密度化を実現しうることを見出し
た。高純度化処理を行ったタングステン粉末を用いて水
素雰囲気中で２０００℃以上に加熱して圧延することに
より高密度・高純度タングステンターゲットを得ること
ができた。高温処理により結晶粒の成長が起こるが、実
質上支障はないことを確認した。As a result of the research conducted by the present inventor,
It has been found that it is necessary to more strictly regulate the density regulation to realize a density of 99.5% or more in order to further reduce the particles. In order to satisfy the requirements of reduction of soft error and reduction of specific resistance, it is necessary to reduce the content of radioactive elements such as U and Th and impurities such as carbon and oxygen. The present inventor has found that a relative density of 99.5% or more can be achieved by heating a sintered body of tungsten powder to 2000 ° C. or more in a hydrogen atmosphere and rolling it. It was possible to obtain a high-density and high-purity tungsten target by heating to 2000 ° C. or higher in a hydrogen atmosphere and rolling using the tungsten powder subjected to the high-purification treatment. It was confirmed that the high temperature treatment causes the growth of crystal grains, but there is substantially no problem.
【０００８】この知見に基づいて、本発明は、（１）相
対密度が９９．５％以上であり、平均粒径が１０μｍを
超え２００μｍ以下であることを特徴とするタングステ
ンスパッタリングターゲット、（２）炭素量３０ｐｐｍ
以下、酸素量２０ｐｐｍ以下及び他の不純物の合計が１
０ｐｐｍ以下であることを特徴とする上記１のタングス
テンスパッタリングターゲット、更には（３）Ｕ及びＴ
ｈが各々０．１ｐｐｂ以下であることを特徴とする上記
１又は２のタングステンスパッタリングターゲットを提
供する。本発明はまた、（４）タングステン粉末の焼結
体を水素雰囲気中で２０００℃以上に加熱し、その後熱
間圧延することを特徴とする、相対密度９９．５％以上
でありそして平均粒径が１０μｍを超え２００μｍ以下
であるタングステンスパッタリングターゲットの製造方
法、（５）ターゲットが、炭素量３０ｐｐｍ以下、酸素
量２０ｐｐｍ以下及び他の不純物の合計が１０ｐｐｍ以
下であることを特徴とする上記４のタングステンスパッ
タリングターゲットの製造方法、更には（６）ターゲッ
トに含まれるＵ及びＴｈが各々０．１ｐｐｂ以下である
ことを特徴とする上記４又は５のタングステンスパッタ
リングターゲットの製造方法をも提供するものである。Based on this finding, the present invention provides (1) a tungsten sputtering target having a relative density of 99.5% or more and an average particle size of more than 10 μm and 200 μm or less, (2) Carbon amount 30ppm
Below, the oxygen content is less than 20ppm and the total of other impurities is 1
0 ppm or less, the tungsten sputtering target of the above 1, further (3) U and T
There is provided the tungsten sputtering target according to the above 1 or 2, wherein h is 0.1 ppb or less. The present invention also provides (4) a sintered body of tungsten powder, which is heated to 2000 ° C. or higher in a hydrogen atmosphere and then hot-rolled, having a relative density of 99.5% or higher and an average grain size. Is more than 10 μm and 200 μm or less, (5) The target has a carbon content of 30 ppm or less, an oxygen content of 20 ppm or less, and a total of other impurities of 10 ppm or less. The present invention also provides a method for producing a sputtering target, and (6) the method for producing a tungsten sputtering target according to 4 or 5 above, wherein U and Th contained in the target are each 0.1 ppb or less.
【０００９】[0009]
【作用】ＶＬＳＩへの成膜用タングステンターゲットと
しては、高密度であることそして更には高純度であるこ
とが重要である。相対密度を９９．５％以上とすること
により内部気孔の低減によりパーティクルを一層減少さ
せることができる。炭素量３０ｐｐｍ以下、酸素量２０
ｐｐｍ以下そして他の不純物の合計が１０ｐｐｍ以下と
従来より更に厳しい限定を加えることは、膜の比抵抗低
減に寄与する。Ｕ及びＴｈが各々０．１ｐｐｂ以下とす
ることにより、ソフトエラーによる信頼性を極限まで低
下させることができる。高密度化を実現するために、高
温での熱間圧延が必要となるが、高純度材であるため不
可避的に高温処理に伴い粒成長が起こり、平均粒径が１
０μｍを超え２００μｍ以下の範囲となる。水素処理の
温度は可能な限り高い方が密度上昇、酸素低減、炭素低
減のいずれにも有効であり、特に酸素低減に有効であ
る。安定的に酸素を２０ｐｐｍ以下とするためには、水
素での熱処理温度を２０００℃以上とすることが必要で
ある。Function It is important that the tungsten target for film formation on VLSI has high density and further high purity. By setting the relative density to 99.5% or more, the number of particles can be further reduced by reducing the internal pores. Carbon amount 30ppm or less, oxygen amount 20
Adding a stricter limit of less than ppm and the total of other impurities of less than 10 ppm contributes to the reduction of the specific resistance of the film. By setting each of U and Th to be 0.1 ppb or less, the reliability due to the soft error can be lowered to the limit. To achieve high density, hot rolling at high temperature is required, but since it is a high-purity material, grain growth inevitably occurs with high-temperature treatment, and the average grain size is 1
The range is more than 0 μm and 200 μm or less. When the temperature of the hydrogen treatment is as high as possible, it is effective for increasing the density, reducing oxygen and reducing carbon, and is particularly effective for reducing oxygen. In order to stably reduce oxygen to 20 ppm or less, it is necessary to set the heat treatment temperature with hydrogen to 2000 ° C. or higher.
【００１０】[0010]
【実施例】高純度タングステン粉末を製造するには、原
料タングステン化合物或いは原料タングステンメタルを
まずメタタングステン酸アンモニウム（ＡＭＴ）のよう
な水溶液の形とし、該水溶液を種々の方法で精製した
後、パラタングステン酸アンモニウム（ＡＰＴ）のよう
な精製結晶を水溶液から晶出させ、該精製タングステン
化合物結晶を水素還元してタングステン粉末を得るのが
一般的方法である。従来から提案されている幾つかの高
純度タングステン製造法として、例えば、特公平２−２
７２８６号、特公平２−２７２８７号或いは特開平１−
１７２２２６号は、ＡＭＴ（メタタングステン酸アンモ
ニウム）を原料として、強酸性領域で晶出させた結晶性
の良い水溶性タングステン化合物を経由することによっ
て高純度ＡＰＴ（パラタングステン酸アンモニウム）を
製造する方法を開示している。また、特開昭６１−２９
５３３８号、特開昭６１−２９５３３９号或いは特開昭
６１−２９５３４０号には、タングステン粉末を原料と
し過酸化水素水を使用して得た水溶液を強酸性陽イオン
交換樹脂と接触させ、その後液の濃縮固形物を水素還元
する方法を開示している。EXAMPLES In order to produce high-purity tungsten powder, the raw material tungsten compound or raw material tungsten metal is first formed into an aqueous solution such as ammonium metatungstate (AMT), and the aqueous solution is purified by various methods, and then the It is a general method to crystallize a purified crystal such as ammonium tungstate (APT) from an aqueous solution and reduce the purified tungsten compound crystal with hydrogen to obtain a tungsten powder. Some of the methods for producing high-purity tungsten that have been conventionally proposed include, for example, Japanese Patent Publication No. 2-2.
No. 7286, Japanese Patent Publication No. 27287/1990 or Japanese Patent Laid-Open No.
No. 172226 is a method for producing high-purity APT (ammonium paratungstate) by using AMT (ammonium metatungstate) as a raw material and passing through a water-soluble tungsten compound having good crystallinity which is crystallized in a strongly acidic region. Disclosure. Also, JP-A-61-29
5338, JP-A-61-295339 or JP-A-61-295340, an aqueous solution obtained by using hydrogen peroxide as a raw material of tungsten powder is contacted with a strongly acidic cation exchange resin, and then the solution is added. Discloses a method for reducing concentrated solids of hydrogen with hydrogen.
【００１１】本件出願人は先に、更に高純度のタングス
テン粉末を製造する方法として、特願平４−２２７７７
９号において、（イ）メタタングステン酸アンモニウム
を水に溶解して含タングステン水溶液を生成し、（ロ）
該含タングステン水溶液をリン酸型又はアミドキシム型
キレート樹脂と接触させて精製パラタングステン酸アン
モニウム結晶析出母液を生成し、そして（ハ）該精製パ
ラタングステン酸アンモニウム結晶析出母液のｐＨを調
整後加熱することによりパラタングステン酸アンモニウ
ム結晶を析出させることを特徴とする高純度パラタング
ステン酸アンモニウム結晶の製造方法を提唱した。この
提唱方法においては、前記含タングステン水溶液と前記
キレート樹脂を接触させるに先立ち、含タングステン水
溶液のｐＨを５．０〜７．０に調整することが好まし
い。前記精製パラタングステン酸アンモニウム結晶析出
は母液にアンモニア水を添加してｐＨを６．０〜８．０
の範囲に調整し、５０℃以上に加熱することが好まし
い。この方法は、従来はＡＭＴ水溶液から一旦タングス
テン酸等の水溶性の化合物結晶を晶出させる方法等によ
って精製した後、ＡＰＴの精製結晶（高純度タングステ
ン原料）を得る方法を採っていたのに対し、ＡＭＴ水溶
液を、リン酸型キレート樹脂或いはアミドキシム型キレ
ート樹脂を充填したカラムに通液し、液中のＵ、Ｔｈ等
の放射性元素及びＦｅ等の遷移元素を吸着除去して調製
した精製ＡＭＴ水溶液から高純度のＡＰＴ結晶を得るも
のである。リン酸型キレート樹脂或いはアミドキシム型
キレート樹脂は、ＡＭＴ液中のＵ、Ｔｈ等の放射性元素
及びＦｅ等の遷移元素と錯体を形成してそれらを効率的
に吸着除去する。The applicant of the present invention has previously proposed, as a method for producing a higher-purity tungsten powder, Japanese Patent Application No. 4-22777.
In No. 9, (a) ammonium metatungstate is dissolved in water to produce a tungsten-containing aqueous solution, (b)
Contacting the tungsten-containing aqueous solution with a phosphoric acid type or amidoxime type chelating resin to produce a purified ammonium paratungstate crystal precipitation mother liquor, and (c) heating after adjusting the pH of the purified ammonium paratungstate crystal precipitation mother liquor. We proposed a method for producing high-purity ammonium paratungstate crystals, which is characterized by precipitating ammonium paratungstate crystals. In this proposed method, it is preferable to adjust the pH of the tungsten-containing aqueous solution to 5.0 to 7.0 before bringing the tungsten-containing aqueous solution into contact with the chelate resin. For the precipitation of the purified ammonium paratungstate crystals, the pH is adjusted to 6.0 to 8.0 by adding aqueous ammonia to the mother liquor.
It is preferable that the temperature is adjusted to within the above range and heating to 50 ° C. or higher. In contrast to this method, conventionally, a method of once obtaining a purified crystal of APT (high-purity tungsten raw material) after purification by a method of once crystallizing a water-soluble compound crystal such as tungstic acid from an AMT aqueous solution was adopted. , AMT aqueous solution is passed through a column packed with a phosphoric acid type chelating resin or an amidoxime type chelating resin, and radioactive elements such as U and Th and transition elements such as Fe in the liquid are adsorbed and removed to prepare purified AMT aqueous solution To obtain a high-purity APT crystal. The phosphoric acid type chelate resin or the amidoxime type chelate resin forms a complex with a radioactive element such as U and Th in the AMT solution and a transition element such as Fe, and efficiently adsorbs and removes them.
【００１２】ＡＰＴ結晶を洗浄、乾燥、ばい焼した後無
水のタングステン酸とし、その後、水素還元することに
より高純度タングステン粉末を得ることができる。A high-purity tungsten powder can be obtained by washing, drying and roasting the APT crystal to obtain anhydrous tungstic acid, followed by hydrogen reduction.
【００１３】本発明では、こうした従来からの提唱方法
を総称して高純度化処理と定義し、不純物（酸素、炭素
を除く）の合計が１０ｐｐｍ以下そしてＵ及びＴｈが各
々０．１ｐｐｂ以下とすることができるものあれば、任
意の従来からの精製方法を使用することができるし、こ
の要件を満たす市販のタングステン粉末を使用すること
ができる。In the present invention, these conventional methods are collectively defined as a purification treatment, and the total amount of impurities (excluding oxygen and carbon) is 10 ppm or less and U and Th are each 0.1 ppb or less. Any conventional refining method can be used, provided that commercially available tungsten powders that meet this requirement can be used.
【００１４】高純度タングステン粉末は、ＣＩＰと続い
てのＨＩＰ処理により、或いはホットプレスすることに
より焼結され、タングステンブリケット（密度：９５〜
９８％）とされる。その後、タングステンブリケットは
水素熱処理・圧延される。水素処理の温度は可能な限り
高い方が密度上昇、酸素低減、炭素低減のいずれにも有
効であり、特に酸素低減に有効である。安定的に酸素を
２０ｐｐｍ以下とし、かつ健全な材料を得るためには水
素雰囲気での加熱を２０００℃以上として圧延すること
が必要である。高温処理が必要となるが、高純度材であ
るため不可避的に高温処理に伴い粒成長が起こり、平均
粒径が１０μｍを超え２００μｍ以下の範囲となる。The high-purity tungsten powder is sintered by CIP followed by HIP treatment or hot pressing to obtain a tungsten briquette (density: 95-
98%). Then, the tungsten briquette is subjected to hydrogen heat treatment and rolling. When the temperature of the hydrogen treatment is as high as possible, it is effective for increasing the density, reducing oxygen and reducing carbon, and is particularly effective for reducing oxygen. In order to stably obtain oxygen of 20 ppm or less and to obtain a sound material, it is necessary to perform heating in a hydrogen atmosphere at 2000 ° C. or more for rolling. High-temperature treatment is required, but since it is a high-purity material, grain growth inevitably occurs with high-temperature treatment, and the average grain size exceeds 10 μm and is 200 μm or less.
【００１５】こうして、次の特性を有するタングステン
ターゲットが得られる： （１）密度：９９．５％ （２）０：２０ｐｐｍ以下 （３）Ｃ：３０ｐｐｍ以下 （４）他の不純物の合計：１０ｐｐｍ以下 （５）Ｕ及びＴｈ：各０．１ｐｐｂ以下 （６）平均粒径：１０〜２００μｍThus, a tungsten target having the following characteristics is obtained: (1) Density: 99.5% (2) 0: 20 ppm or less (3) C: 30 ppm or less (4) Total of other impurities: 10 ppm or less (5) U and Th: 0.1 ppb or less for each (6) Average particle size: 10 to 200 μm
【００１６】（実施例）原料ＡＭＴ粉（Ｕ：０．１ｐｐ
ｂ、Ｔｈ：０．５ｐｐｂ、Ｆｅ：０．２ｐｐｍ）を純水
で溶解し、濃度を５００ｇ−ＡＭＴ／ｌに調製した。こ
のＡＭＴ溶液をＮＨ4 ＯＨａｑ．（ＥＬグレード）を用
いてｐＨ＝６．０に調整し、ポンプを用いてＬＶ（線速
度）値０．２ｍ／時間で室温（２１℃）にて吸着カラム
に連続通液した。通液後の精製ＡＭＴ液に、ＮＨ4 ＯＨ
ａｑ．（ＥＬグレード）を必要量加え、８０℃に一晩保
温し、ＡＰＴ結晶を晶出させた。晶出したＡＰＴ結晶を
ろ過しそして純水で洗浄した後、乾燥、ばい焼（大気雰
囲気、３００℃−５時間）及び還元（水素雰囲気での２
段還元、５６５℃−８０分＋１０５０℃−３時間）を行
った。(Example) Raw material AMT powder (U: 0.1 pp)
b, Th: 0.5 ppb, Fe: 0.2 ppm) was dissolved in pure water to adjust the concentration to 500 g-AMT / l. This AMT solution was added to NH 4 OHaq. (EL grade) was used to adjust the pH to 6.0, and an LV (linear velocity) value of 0.2 m / hour was continuously passed through the adsorption column at room temperature (21 ° C.) using a pump. NH 4 OH was added to the purified AMT solution after passing through.
aq. The required amount of (EL grade) was added, and the mixture was kept at 80 ° C. overnight to crystallize APT crystals. The crystallized APT crystal was filtered and washed with pure water, then dried, roasted (atmosphere atmosphere, 300 ° C. for 5 hours) and reduced (2 in hydrogen atmosphere).
Step reduction, 565 ° C-80 minutes + 1050 ° C-3 hours) was performed.
【００１７】高純度タングステン粉末をホットプレスす
ることにより焼結し、密度９７％のブリケットとした。
その後、２０００℃で水素熱処理し、圧延した。製造さ
れたタングステンターゲットの、ターゲットとしての特
性、および得られた膜の特性は以下の表１及び２に示し
た通りであった。High-purity tungsten powder was hot-pressed to be sintered into a briquette having a density of 97%.
Then, it was heat-treated with hydrogen at 2000 ° C. and rolled. The characteristics of the manufactured tungsten target as a target and the characteristics of the obtained film were as shown in Tables 1 and 2 below.
【００１８】[0018]
【表１】 [Table 1]
【００１９】[0019]
【表２】 [Table 2]
【００２０】（比較例１）実施例と同様の原料粉を用い
てターゲットを製造したが、水素熱処理温度を１６００
℃とした。その結果、０：２５ｐｐｍ、Ｃ：１０ｐｐ
ｍ、密度：９９．１％、膜抵抗：８．９μΩ・ｃｍ、パ
ーティクル発生数：０．５μｍ以上のものが３ケそして
０．３〜０．５μｍ範囲のものが１５ケとなった。水素
熱処理温度を２０００℃以上と高くする必要性がわか
る。(Comparative Example 1) A target was manufactured using the same raw material powder as in Example, but the hydrogen heat treatment temperature was set to 1600.
℃ was made. As a result, 0:25 ppm, C: 10 pp
m, density: 99.1%, film resistance: 8.9 μΩ · cm, number of particles generated: 3 in 0.5 μm or more and 15 in 0.3 to 0.5 μm range. It can be seen that it is necessary to raise the hydrogen heat treatment temperature to 2000 ° C. or higher.
【００２１】（比較例２）原料精製工程が不十分であっ
た、Ｕ：１ｐｐｂ、Ｔｈ：１ｐｐｂの原料を用いて実施
例と同様にタングステンターゲットを製造した。その結
果、生成膜のソフトエラー確率は５００時間で１回とな
り、信頼性が大幅に低下した。(Comparative Example 2) A tungsten target was manufactured in the same manner as in the example using the raw materials of U: 1ppb and Th: 1ppb for which the raw material purification step was insufficient. As a result, the soft error probability of the produced film was once in 500 hours, and the reliability was significantly lowered.
【００２２】[0022]
【発明の効果】パーティクル低下による信頼性向上、ソ
フトエラー低減による信頼性向上、膜特性改善による高
性能化により一層高集積化した微細幅のタングステン膜
の生成を可能ならしめる。According to the present invention, it is possible to form a highly-integrated fine-width tungsten film by improving reliability by reducing particles, improving reliability by reducing soft errors, and improving performance by improving film characteristics.
Claims (6)
粒径が１０μｍを超え２００μｍ以下であることを特徴
とするタングステンスパッタリングターゲット。1. A tungsten sputtering target having a relative density of 99.5% or more and an average particle size of more than 10 μm and 200 μm or less.
ｍ以下及び他の不純物の合計が１０ｐｐｍ以下であるこ
とを特徴とする請求項１のタングステンスパッタリング
ターゲット。2. A carbon amount of 30 ppm or less and an oxygen amount of 20 pp
The tungsten sputtering target according to claim 1, wherein the sum of m or less and other impurities is 10 ppm or less.
ることを特徴とする請求項１又は２のタングステンスパ
ッタリングターゲット。3. The tungsten sputtering target according to claim 1, wherein U and Th are each 0.1 ppb or less.
中で２０００℃以上に加熱し、その後熱間圧延すること
を特徴とする、相対密度９９．５％以上でありそして平
均粒径が１０μｍを超え２００μｍ以下であるタングス
テンスパッタリングターゲットの製造方法。4. A tungsten powder sintered body is heated to 2000 ° C. or higher in a hydrogen atmosphere, and then hot-rolled, with a relative density of 99.5% or higher and an average particle size of 10 μm. A method for manufacturing a tungsten sputtering target, which exceeds 200 μm.
酸素量２０ｐｐｍ以下及び他の不純物の合計が１０ｐｐ
ｍ以下であることを特徴とする請求項４のタングステン
スパッタリングターゲットの製造方法。5. The target has a carbon content of 30 ppm or less,
Oxygen amount 20ppm or less and the total of other impurities is 10pp
The method for manufacturing a tungsten sputtering target according to claim 4, wherein the sputtering target is less than or equal to m.
０．１ｐｐｂ以下であることを特徴とする請求項４又は
５のタングステンスパッタリングターゲットの製造方
法。6. The method for producing a tungsten sputtering target according to claim 4, wherein U and Th contained in the target are each 0.1 ppb or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24603193A JPH0776771A (en) | 1993-09-08 | 1993-09-08 | Tungsten sputtering target |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24603193A JPH0776771A (en) | 1993-09-08 | 1993-09-08 | Tungsten sputtering target |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0776771A true JPH0776771A (en) | 1995-03-20 |
Family
ID=17142427
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24603193A Withdrawn JPH0776771A (en) | 1993-09-08 | 1993-09-08 | Tungsten sputtering target |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0776771A (en) |
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| CN108140560B (en) * | 2015-10-22 | 2023-04-11 | 应用材料公司 | System and method for low resistivity physical vapor deposition of tungsten films |
| JP2018537849A (en) * | 2015-10-22 | 2018-12-20 | アプライド マテリアルズ インコーポレイテッドＡｐｐｌｉｅｄ Ｍａｔｅｒｉａｌｓ，Ｉｎｃｏｒｐｏｒａｔｅｄ | System and method for low resistance physical vapor deposition of tungsten films |
| WO2017074728A1 (en) * | 2015-10-27 | 2017-05-04 | Tosoh Smd, Inc. | Method of making low resistivity tungsten sputter targets and targets made thereby |
| US20180312960A1 (en) * | 2015-10-27 | 2018-11-01 | Tosoh Smd, Inc. | Method of making low resistivity tungsten sputter targets and targets made thereby |
| JP2019090071A (en) * | 2017-11-10 | 2019-06-13 | Ｊｘ金属株式会社 | Tungsten sputtering target, and manufacturing method thereof |
| US20200370167A1 (en) * | 2017-11-10 | 2020-11-26 | Jx Nippon Mining & Metals Corporation | Tungsten Sputtering Target And Method For Producing Same |
| WO2019092969A1 (en) * | 2017-11-10 | 2019-05-16 | Ｊｘ金属株式会社 | Tungsten sputtering target and method for producing same |
| AT522305A5 (en) * | 2017-11-10 | 2021-10-15 | Jx Nippon Mining & Metals Corp | Tungsten Sputtering Target and Process for Its Manufacture |
| AT522305B1 (en) * | 2017-11-10 | 2022-10-15 | Jx Nippon Mining & Metals Corp | Tungsten sputtering target and method of making same |
| JP2023076733A (en) * | 2017-11-10 | 2023-06-01 | Ｊｘ金属株式会社 | tungsten sputtering target |
| US11939661B2 (en) | 2017-11-10 | 2024-03-26 | Jx Metals Corporation | Tungsten sputtering target and method for manufacturing the same |
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