JPH0449502B2 - - Google Patents
Info
- Publication number
- JPH0449502B2 JPH0449502B2 JP61094761A JP9476186A JPH0449502B2 JP H0449502 B2 JPH0449502 B2 JP H0449502B2 JP 61094761 A JP61094761 A JP 61094761A JP 9476186 A JP9476186 A JP 9476186A JP H0449502 B2 JPH0449502 B2 JP H0449502B2
- Authority
- JP
- Japan
- Prior art keywords
- acid
- concentration
- aqueous solution
- nitric acid
- perchloric
- 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.)
- Expired - Lifetime
Links
- 229910052776 Thorium Inorganic materials 0.000 claims description 33
- 229910052770 Uranium Inorganic materials 0.000 claims description 33
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical compound OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 claims description 31
- 238000000034 method Methods 0.000 claims description 21
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 18
- 229910017604 nitric acid Inorganic materials 0.000 claims description 18
- 239000007864 aqueous solution Substances 0.000 claims description 17
- 229910052791 calcium Inorganic materials 0.000 claims description 17
- 229910052749 magnesium Inorganic materials 0.000 claims description 16
- 239000002253 acid Substances 0.000 claims description 15
- 239000003957 anion exchange resin Substances 0.000 claims description 11
- 239000000919 ceramic Substances 0.000 claims description 11
- 239000000463 material Substances 0.000 claims description 11
- 230000002285 radioactive effect Effects 0.000 claims description 11
- 239000011347 resin Substances 0.000 claims description 11
- 229920005989 resin Polymers 0.000 claims description 11
- 239000002994 raw material Substances 0.000 claims description 10
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 9
- 238000004519 manufacturing process Methods 0.000 claims description 8
- 239000000758 substrate Substances 0.000 claims description 8
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 6
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 6
- 150000001875 compounds Chemical class 0.000 claims description 6
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 4
- 150000007513 acids Chemical class 0.000 claims description 3
- 229910052726 zirconium Inorganic materials 0.000 description 17
- 229910052782 aluminium Inorganic materials 0.000 description 12
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 9
- 238000002474 experimental method Methods 0.000 description 7
- 238000000926 separation method Methods 0.000 description 7
- 239000000243 solution Substances 0.000 description 7
- 150000002500 ions Chemical class 0.000 description 6
- 238000001179 sorption measurement Methods 0.000 description 6
- 238000007796 conventional method Methods 0.000 description 5
- 238000009826 distribution Methods 0.000 description 5
- 238000005192 partition Methods 0.000 description 5
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 4
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 4
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 3
- 239000000292 calcium oxide Substances 0.000 description 3
- 235000012255 calcium oxide Nutrition 0.000 description 3
- 238000010828 elution Methods 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- VLTRZXGMWDSKGL-UHFFFAOYSA-M perchlorate Inorganic materials [O-]Cl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-M 0.000 description 3
- 229910002651 NO3 Inorganic materials 0.000 description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 230000005262 alpha decay Effects 0.000 description 2
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 238000005349 anion exchange Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000003480 eluent Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 238000005342 ion exchange Methods 0.000 description 2
- 239000000395 magnesium oxide Substances 0.000 description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical class O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 2
- 230000001681 protective effect Effects 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
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 238000004131 Bayer process Methods 0.000 description 1
- 229910020366 ClO 4 Inorganic materials 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
- 239000003463 adsorbent Substances 0.000 description 1
- -1 aluminum compound Chemical class 0.000 description 1
- 229910001570 bauxite Inorganic materials 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 239000002738 chelating agent Substances 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000010292 electrical insulation Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000003456 ion exchange resin Substances 0.000 description 1
- 229920003303 ion-exchange polymer Polymers 0.000 description 1
- 238000002386 leaching Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 235000010755 mineral Nutrition 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000003947 neutron activation analysis Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Compositions Of Oxide Ceramics (AREA)
Description
（産業上の利用分野）
本発明は、放射性元素であるＵおよびTh濃度
が極めて低いICセラミツク基板用材料の製造方
法に関するものである。
（従来の技術）
アルミナ焼結体は電気絶縁性にすぐれ、機械的
強度が高いなどすぐれた性質を有するためにLSI
或いは超LSIなどの保護容器すなわちICパツケー
ジとして大量に用いられる。
しかしながら、このICパツケージ材料の中に
放射性元素のうちα崩壊をするＵおよびThが極
微量でも存在すると、これらの元素の崩壊過程で
放出されるα粒子がICチツプ中に侵入し、電離
作用を生じせしめ、大量の電子正孔対を生成し、
ダイナミツクRAM（Randam Access Memory）
およびCCD（Charge Coupled Device）にソフト
エラーを誘起することが、16 th Annual
Proceedings of 1978 International Reliability
Physis Symposium，April 18−20，1987により
知られている。このソフトエラー対策として、半
導体メモリー装置にエラー訂正回路を組み込む
か、あるいはチツプにα粒子保護のためにα粒子
保護材をコーテイングする等が考えられたが、メ
モリー装置の高集積化に障害をもたらすばかりで
なく製造コストそのものも増大してしまう。した
がつてパツケージ材料中のＵおよびTh濃度をソ
フトエラーを生じさせない水準にまで低減させる
ことが望まれていた。このような目的でアルミナ
中のＵおよびTh濃度の低減への試みがいくつか
試みられている。
アルミナは工業的には主にバイヤー法によりボ
ーキサイトを原料として作られる。その過程で、
含水酸化チタン含有吸着剤を用いてＵの吸着除去
させる方法が、特開昭56−140026号により、また
製造されたアルミナ微粉を希薄な鉱酸中で洗浄す
ることによる浸出法によりＵおよびTh濃度を低
減させる方法が特開昭56−164013号により開示さ
れている。さらに、特開昭59−30719号により、
微量の放射性元素を含有するアルミニウム化合物
の溶液をキレート化剤と接触させ、微量の放射性
元素を吸着分離せしめ、次いで該溶液からアルミ
ニウム水酸化物、又は酸化物を製造することを特
徴とする放射性元素含有量の低いアルミニウム水
酸化物、又は酸化物の製造方法が開示されてい
る。
（発明が解決しようとする問題点）
しかしながら、特開昭56−140026号記載の方法
によれば、Ｕの除去のみが行われ、特開昭56−
164013号によれば、アルミナ中のＵおよびTh濃
度を10ppbより低くすることはできないという問
題点があつた。また、特開昭59−30719号によれ
ばアルミナ中のＵ濃度を1ppb以下にすることは
できるが、Ｕの除去のみが行われThの除去は行
われないという問題点があつた。
（問題点を解決するための手段）
本発明は、前記従来方法の有する問題点あるい
は欠点を除去、改善することのできる方法を提供
することを目的とするものであり、特許請求の範
囲記載の放射性元素濃度の極めて低いICセラミ
ツク基板用材料の製造方法を提供することによつ
て、前記目的を達成することができる。すなわ
ち、ICセラミツク基板用材料となるAl化合物、
またはAl化合物を主体とし、残部Mg，Ca，Zrの
なかから選ばれるいずれか少なくとも１種を含む
化合物からなるセラミツク原料を、硝酸、過塩素
酸モル濃度がそれぞれ１〜14M，0.1〜12Mであ
る硝酸および／または過塩素酸あるいはそれらを
主体とした混酸水溶液中に溶解させた後、この水
溶液を強塩基性陰イオン交換樹脂と２回以上接触
させることにより、前記原料の前記水溶液中に溶
出したＵおよびThを前記樹脂に吸着させた後、
常法に従つて、前記水溶液から前記原料の水酸化
物を経て、または水酸化物を経ることなくＵおよ
びTh濃度が1.5ppb以下である酸化物を製造する
ことを特徴とする放射性元素濃度の極めて低い
ICセラミツク基板用材料の製造方法に関するも
のである。
ここで、本発明で使用する前記強塩基性陰イオ
ン交換樹脂は、下記(a)−(b)のなかから選ばれるい
ずれか少なくとも１種の樹脂であることが好まし
い。
なる構造を有するスチレン系強塩基性陰イオン交
換樹脂。
なる構造を有するスチレン系強塩基性陰イオン交
換樹脂。
次に本発明を詳細に説明する。
今日、ICメモリーが256Kビツトの実用段階に
入り、1Mから4Mビツトの時代に突入しようとし
ていることから、ますますICセラミツク基板中
に放射性元素ＵおよびThさらに少ないことが切
実に要求されるようになつているのに鑑み、本発
明者らは前記ＵおよびThの経済的かつ効率の良
い除去方法について研究した結果、上記従来法に
比し、格段にすぐれた方法に想到して本発明を完
成した。
次に、本発明を実験データを用いて詳細に説明
する。ところで、イオン交換法による分離は溶液
中に含まれる各種イオンのイオン交換樹脂に対す
る吸着度の差を利用して行われる。樹脂層に吸着
される１種の元素と、溶液中に存在する前記元素
の分配係数Ｄは次式(1)によつて算出される。
Ｄ＝樹脂層１ml中に吸着される元素の量／溶液１ml中に
存在する元素の量(1)
また、溶離定数Ｅは式(2)により算出される。
Ｅ＝dA／Ｖ (2)
ここで、ｄは断面積Ａのカラムを容積Ｖの溶離
液が通過した後の吸着帯のピークの移動距離を示
す。また、ＥとＤの関係は式(3)のように表され
る。
Ｅ＝（β＋Ｄ）-1 (3)
ここで、βは樹脂の空〓率である。
式(2)において溶離液の単位時間あたりの流量Ｆ＝
Ｖ／ｔを用いると次式の関係が得られる。
ｄ＝（Ｅ／Ａ）×Ｖ＝（EF／Ａ）×ｔ (4)
つまり、ＦおよびＡが一定のものではｔの傾き
すなわち吸着帯の移動速度ｄ／ｔは溶離定数Ｅに
依存することになる。よつて、各元素のＤの値が
異なることによつて生じるＥの値が異なるような
条件で溶離を行えば、各元素は異なつた速度でカ
ラム内を移動し、異なつた時間にカラムから流出
することになり分離が行われる。
本発明者らは、硝酸および／また過塩素酸水溶
液またはさらにこれらの酸にその酸の50％以下の
酸濃度の(a)塩酸、(b)硫酸，(c)酢酸、(d)フツ化水素
酸を加えた混酸の水溶液中に溶解されているAl，
Ca，Mg，Zr，Ｕ，Thのそれぞれのイオンの吸
着実験を強塩基性陰イオン交換樹脂（商品名：
Diaion SA ＃100）を用いて行つた。
実験は一定量の前記水溶液に一定量の乾燥した
前記樹脂を加え攪拌しながら約24時間放置し、水
溶液中の各イオンの濃度の変化を分析により調
べ、濃度の減少量から樹脂に吸着されたイオンの
量を計算により求めた。分配係数は(1)式により算
出した。
以上の実験から得られた分配係数と硝酸モル濃
度との関係を第１図に示す。同図によりわかるよ
うに硝酸濃度1M以上において前記分配係数Ｄの
値は１以上となり7M〜8Mにおいて最大となる。
Al，Mg，Ca，ZrのＤは全硝酸モル濃度におい
て零であり、すなわち吸着されないことが明らか
となつた。
また、過塩素酸モル濃度と分配係数の関係を第
２図に示す。ＵおよびThともに前記分配係数の
値は過塩素酸モル濃度が2M付近で最小値をとり、
低モル数側および高モル数側で大きくなつてい
る。AlおよびMgは2M以上の濃度範囲において、
10を超えることはなくＵおよびThの値に比べか
なり小さい値となつている。CaおよびZrについ
て得られた分配係数の過塩素酸モル濃度依存性は
Ｕのそれと類似しており、CaおよびZrとＵとの
分離は困難であると推考される。
さらに硝酸と過塩素酸の混酸については第１
図、第２図に示すＤの値の中間的な値が得られる
ことがわかり、(a)塩酸、(b)硫酸，(c)酢酸、(d)フツ
化水素酸をそれぞれ硝酸、過塩素酸のいずれか少
なくとも１種の酸濃度の50％以下を加えた場合に
は、分配係数の値は、加えられた(a)〜(d)の量の増
加とともに小さくなる傾向が得られた。
以下に上記の結果をもとにして、硝酸中のAl，
Mg，Ca，Zr，Ｕ，Thについてカラム法を用い
たイオン交換分離の条件を計算により下記の如く
求めた。
第１図に示したＤの値から式(4)によつて計算さ
れた各元素のカラム中での移動距離ｄと時間ｔと
の関係を第３図Ａ，Ｂに示す。ここでＡおよびＦ
の値としては実際の実験に用いた値である1.13
cm2，２ml／minを用いた。樹脂層長は26cm、上部
の液層部は２cmとした。また硝酸濃度は7Mとし
た。その時のＥの値は、式(3)を用いて計算する
と、Al，Mg，Ca，Zrについては2.5，Ｕおよび
ThのＥはそれぞれ0.069，0.0053となる。ここで
βは本実験条件では約0.4である。
第３図Ｂに示された結果から推考して、Al，
Mg，Ca，ZrとＵ，Thの流出時間が異なるため、
Ｕ，Thは流出せずにAl，Mg，Ca，Zrのみが流
出してくる液を採取することによりＵおよびTh
を除去することができることがわかる。なお、こ
のようにしてＵおよびThを吸着除去し、次いで
常法に従つて得られるAl，Mg，Ca，Zrの酸化物
中に含まれるＵおよびTh濃度を、いずれの酸化
物においても1.5ppb以下の値とするには、上述し
た強塩基性陰イオン交換樹脂によるＵおよびTh
の吸着分離操作を２回以上行う必要がある。実際
の操業に際してはAl，Mg，Ca，Zrの硝酸溶液と
硝酸を交互にカラム中に送り込み、間歇的に高純
度化されたAl，Mg，Ca，Zr水溶液を採取するこ
とにより連続運転が可能である。またこの場合歩
留りは100％に極めて近いことが期待される。
なお、ここで特徴的な事はAl，Mg，Ca，Zrが
同じ挙動をするため、この分離法はAl，Mg，
Ca，Zr個々の精製に限らず、これら元素を最終
的に望まれるセラミツク組成に混合されたものに
ついても個々の精製と同じ結果の得られることが
わかる。
上記実験においては非常に小さいカラムを用い
たが、実際の工業化のための装置の大型化は容易
であり、また樹脂も工業用の粗粒のものを使用す
ることができ、このようにすることによつて操業
時間は著しく短縮される。
次に本発明を実施例について説明する。
実施例 １
原料として市販特級のAl（NO3）3・9H2Ｏ，Ca
（NO3）2・4H2Ｏ，Mg（NO3）2・6H2ＯおよびZr
（NO3）4水溶液を用いた。
カラムは内径12mmφのガラス製で、その中に強
塩性陰イオン交換樹脂ダイヤイオンSA＃100（三
菱化成製）を26cm長になるように詰めたものを用
いた。他の薬品はすべて市販の特級品を用いた。
アルミナ、カルシア、マグネシアおよびジルコ
ニアの製造プロセスを第４図に示す。なお、水酸
化物を経由させるか否かは使用する原料の種類な
ど必要に応じて適宜に選択した。ここで陰イオン
交換分離により精製された硝酸塩水溶液から酸化
物を得るには公知の慣用方法を用いることが可能
である。
得られた酸化物中のＵおよびTh濃度を中性子
放射化分析法により求めた。その結果を第１表に
示す。比較のため原料として用いた硝酸塩を直接
焼成して製作した酸化物の分析結果も示した。
ZrO2を除いて、ＵおよびTh濃度は約1ppbと極
めて小さい値のものが得られており、このような
極めて低い濃度は今までに知られていない。
ZrO2について得られた値はAl2O3，CaO，
MgO中のＵ，Th濃度に比べると約１桁大きい
が、ZrO2中のＵ，Th濃度としては今までに知ら
れていないような低い値である。
(Industrial Application Field) The present invention relates to a method for manufacturing an IC ceramic substrate material having extremely low concentrations of U and Th, which are radioactive elements. (Prior technology) Alumina sintered bodies have excellent properties such as excellent electrical insulation and high mechanical strength, so they are used in LSI applications.
Alternatively, it is used in large quantities as a protective container for ultra-LSI devices, that is, an IC package. However, if even trace amounts of radioactive elements such as U and Th, which undergo α-decay, are present in this IC package material, the α-particles released during the decay process of these elements will enter the IC chip and cause ionization. generate a large amount of electron-hole pairs,
Dynamic RAM (Random Access Memory)
The 16th Annual
Proceedings of 1978 International Reliability
Physis Symposium, April 18-20, 1987. As a countermeasure against this soft error, it has been considered to incorporate an error correction circuit into the semiconductor memory device or to coat the chip with an alpha particle protective material to protect alpha particles, but this poses an obstacle to the high integration of memory devices. Not only that, but the manufacturing cost itself also increases. Therefore, it has been desired to reduce the U and Th concentrations in the package material to a level that does not cause soft errors. For this purpose, several attempts have been made to reduce the U and Th concentrations in alumina. Industrially, alumina is mainly produced using bauxite as a raw material by the Bayer process. In the process,
A method for adsorbing and removing U using an adsorbent containing hydrous titanium oxide is disclosed in JP-A-56-140026, and a leaching method in which the produced alumina fine powder is washed in dilute mineral acid is used to reduce U and Th concentrations. A method for reducing this is disclosed in JP-A-56-164013. Furthermore, according to Japanese Patent Application Laid-Open No. 59-30719,
A radioactive element characterized by contacting a solution of an aluminum compound containing a trace amount of a radioactive element with a chelating agent, adsorbing and separating the trace amount of the radioactive element, and then producing aluminum hydroxide or oxide from the solution. A method for producing aluminum hydroxide or oxide with a low content is disclosed. (Problems to be Solved by the Invention) However, according to the method described in JP-A-56-140026, only U is removed;
According to No. 164013, there was a problem in that the U and Th concentrations in alumina could not be lowered below 10 ppb. Furthermore, according to JP-A-59-30719, it is possible to reduce the U concentration in alumina to 1 ppb or less, but there is a problem in that only U is removed and Th is not removed. (Means for Solving the Problems) The present invention aims to provide a method that can eliminate and improve the problems and drawbacks of the conventional methods, and the present invention is directed to The above object can be achieved by providing a method for manufacturing an IC ceramic substrate material having an extremely low concentration of radioactive elements. In other words, Al compounds, which are materials for IC ceramic substrates,
Alternatively, a ceramic raw material consisting of a compound mainly containing an Al compound and the remainder containing at least one selected from Mg, Ca, and Zr is prepared using a ceramic material having a molar concentration of nitric acid and perchloric acid of 1 to 14 M and 0.1 to 12 M, respectively. The raw material was dissolved in the aqueous solution by dissolving it in an aqueous solution of nitric acid and/or perchloric acid or a mixed acid mainly composed of them, and then contacting this aqueous solution with a strongly basic anion exchange resin two or more times. After adsorbing U and Th to the resin,
A method of reducing the concentration of radioactive elements, characterized in that an oxide having a U and Th concentration of 1.5 ppb or less is produced from the aqueous solution through or without passing through the hydroxide of the raw material, according to a conventional method. extremely low
The present invention relates to a method for producing materials for IC ceramic substrates. Here, the strongly basic anion exchange resin used in the present invention is preferably at least one resin selected from the following (a) to (b). A styrene-based strongly basic anion exchange resin with the following structure. A styrene-based strongly basic anion exchange resin with the following structure. Next, the present invention will be explained in detail. Today, as IC memory enters the practical stage of 256K bits and we are about to enter the era of 1M to 4M bits, there is an urgent need to further reduce the radioactive elements U and Th in IC ceramic substrates. As a result of research into an economical and efficient method for removing U and Th, the present inventors came up with a method that is far superior to the above conventional methods and completed the present invention. did. Next, the present invention will be explained in detail using experimental data. Incidentally, separation by the ion exchange method is performed by utilizing the difference in the degree of adsorption of various ions contained in the solution to the ion exchange resin. The distribution coefficient D of one type of element adsorbed on the resin layer and the element present in the solution is calculated by the following equation (1). D=Amount of element adsorbed in 1 ml of resin layer/Amount of element present in 1 ml of solution (1) Further, the elution constant E is calculated by equation (2). E=dA/V (2) Here, d indicates the distance traveled by the peak of the adsorption zone after the volume V of the eluent passes through the column with the cross-sectional area A. Further, the relationship between E and D is expressed as in equation (3). E=(β+D) -1 (3) Here, β is the porosity of the resin. In equation (2), the flow rate of eluent per unit time F=
Using V/t, the following relationship is obtained. d=(E/A)×V=(EF/A)×t (4) In other words, when F and A are constant, the slope of t, that is, the moving speed of the adsorption zone d/t, depends on the elution constant E. become. Therefore, if elution is performed under conditions in which the values of E caused by different values of D for each element are different, each element will move within the column at different speeds and will flow out of the column at different times. As a result, separation takes place. The present inventors have prepared aqueous solutions of nitric acid and/or perchloric acid, or even these acids with an acid concentration of 50% or less of that acid (a) hydrochloric acid, (b) sulfuric acid, (c) acetic acid, (d) fluoride. Al dissolved in an aqueous solution of mixed acid with hydrogen acid added,
Adsorption experiments of Ca, Mg, Zr, U, and Th ions were conducted using strongly basic anion exchange resin (product name:
Diaion SA #100) was used. In the experiment, a certain amount of the dried resin was added to a certain amount of the aqueous solution and left to stand for about 24 hours with stirring.Changes in the concentration of each ion in the aqueous solution were analyzed by analysis. The amount of ions was determined by calculation. The partition coefficient was calculated using equation (1). FIG. 1 shows the relationship between the partition coefficient and nitric acid molar concentration obtained from the above experiment. As can be seen from the figure, the distribution coefficient D has a value of 1 or more when the nitric acid concentration is 1M or more, and reaches a maximum at 7M to 8M. It became clear that D in Al, Mg, Ca, and Zr was zero in the total nitric acid molar concentration, that is, it was not adsorbed. Moreover, the relationship between perchloric acid molar concentration and partition coefficient is shown in FIG. The values of the distribution coefficients for both U and Th take a minimum value when the molar concentration of perchlorate is around 2M,
It becomes larger on the low mole number side and on the high mole number side. Al and Mg in the concentration range of 2M or more,
It does not exceed 10 and is considerably smaller than the values of U and Th. The dependence of the partition coefficients obtained for Ca and Zr on the molar concentration of perchlorate is similar to that of U, and it is assumed that separation of Ca and Zr from U is difficult. Furthermore, regarding the mixed acid of nitric acid and perchloric acid, see Chapter 1.
It was found that values intermediate between the values of D shown in Figure 2 can be obtained, and (a) hydrochloric acid, (b) sulfuric acid, (c) acetic acid, and (d) hydrofluoric acid were replaced with nitric acid and perchloric acid, respectively. When 50% or less of the acid concentration of at least one of the acids was added, the value of the partition coefficient tended to decrease as the amount of added (a) to (d) increased. Below, based on the above results, Al in nitric acid,
The conditions for ion exchange separation using the column method for Mg, Ca, Zr, U, and Th were calculated as follows. FIGS. 3A and 3B show the relationship between the moving distance d of each element in the column and the time t, which was calculated from the value of D shown in FIG. 1 using equation (4). where A and F
The value of is 1.13, which is the value used in the actual experiment.
cm 2 , 2 ml/min was used. The resin layer length was 26 cm, and the upper liquid layer was 2 cm. In addition, the nitric acid concentration was 7M. The value of E at that time is calculated using equation (3), and is 2.5 for Al, Mg, Ca, and Zr, and 2.5 for U and
The E of Th is 0.069 and 0.0053, respectively. Here, β is approximately 0.4 under the present experimental conditions. Inferring from the results shown in Figure 3B, Al,
Because the outflow times of Mg, Ca, Zr and U, Th are different,
U and Th are collected by collecting the liquid in which only Al, Mg, Ca, and Zr flow out without U and Th flowing out.
It turns out that it is possible to remove. In addition, after removing U and Th by adsorption in this way, the U and Th concentrations contained in the oxides of Al, Mg, Ca, and Zr obtained by a conventional method were reduced to 1.5 ppb in all oxides. To obtain the following values, U and Th using the above-mentioned strong basic anion exchange resin
It is necessary to perform the adsorption separation operation twice or more. During actual operation, continuous operation is possible by alternately feeding nitric acid solutions of Al, Mg, Ca, and Zr into the column, and intermittently collecting highly purified aqueous solutions of Al, Mg, Ca, and Zr. It is. In this case, the yield is expected to be very close to 100%. Note that this separation method is unique because Al, Mg, Ca, and Zr behave in the same way.
It can be seen that the same results can be obtained not only by refining Ca and Zr individually, but also by mixing these elements into the final desired ceramic composition. Although a very small column was used in the above experiment, it is easy to increase the size of the equipment for actual industrialization, and it is also possible to use coarse-grained resin for industrial use. This significantly reduces operating time. Next, the present invention will be explained with reference to examples. Example 1 Commercially available special grade Al(NO 3 ) 3.9H 2 O, Ca as a raw material
(NO 3 ) 2・4H 2 O, Mg (NO 3 ) 2・6H 2 O and Zr
(NO 3 ) 4 aqueous solution was used. The column was made of glass with an inner diameter of 12 mm, and a strong salt anion exchange resin Diaion SA #100 (manufactured by Mitsubishi Kasei) was packed in the column to a length of 26 cm. All other chemicals were commercially available special grade products. The manufacturing process of alumina, calcia, magnesia and zirconia is shown in FIG. Note that whether or not to pass through hydroxide was appropriately selected depending on the type of raw material used and other factors. In order to obtain the oxide from the nitrate aqueous solution purified by anion exchange separation, it is possible to use a known conventional method. The U and Th concentrations in the obtained oxide were determined by neutron activation analysis. The results are shown in Table 1. For comparison, we also show the analysis results of an oxide produced by directly firing the nitrate used as a raw material. Except for ZrO 2 , extremely low U and Th concentrations of about 1 ppb have been obtained, and such extremely low concentrations have never been known. The values obtained for ZrO 2 are Al 2 O 3 , CaO,
Although this is about an order of magnitude higher than the U and Th concentrations in MgO, these are the lowest values ever known for U and Th concentrations in ZrO 2 .
【表】
実施例 ２
ＵおよびTh濃度のさらに低い材料を得る必要
のある場合にそなえて前記陰イオン交換の過程を
さらに１回くり返した。その結果によるとすべて
のＵ，Th濃度は第１表に示した値のようになり、
くり返しの効果が極めて大きいことがわかつた。
実施例 ３
前記実施例１で示したと同様の実験をAlおよ
びMgについて過塩素酸水溶液の場合について行
つた。ただし、原料は市販特級のMg（ClO4）2，
CaOおよび金属Al，Zrであり、過塩素酸のモル
濃度は6Mとした。
実験の過程は第４図に示す過程と同様である。
その結果を第２表に示す。この場合もＵ，Thが
有効に除去されていることがわかる。[Table] Example 2 The anion exchange process was repeated one more time in case it was necessary to obtain a material with even lower U and Th concentrations. According to the results, all U and Th concentrations are as shown in Table 1,
It was found that the effect of repetition is extremely large. Example 3 An experiment similar to that shown in Example 1 above was conducted for Al and Mg in the case of an aqueous perchloric acid solution. However, the raw materials are commercially available special grade Mg(ClO 4 ) 2 ,
CaO and metals Al and Zr, and the molar concentration of perchloric acid was 6M. The experimental process was similar to that shown in FIG.
The results are shown in Table 2. It can be seen that U and Th are effectively removed in this case as well.
【表】
実施例 ４
実用化にはカラムの大型化、操作時間の短縮等
を行う必要があるので、カラムの大型化の目安の
ため内径70mmφのカラムに工業用の陰イオン交換
樹脂ダイヤイオンSA10Bを詰めたものを用い、
実施例１と同様のことを行つた。得られるアルミ
ナの品位を損なうことなく毎分0.1の処理が可
能であつた。このことによりさらに大型のカラム
の使用が可能であることがわかる。また、Alの
回収歩留は、ほぼ100％であつた。
（発明の効果）
以上述べたように、本発明によれば、放射性元
素、特にα崩壊を示す放射性元素であるＵ，Th
濃度の極めて低いICセラミツク基板用材料を容
易かつ安定して製造することができるので、今後
のICの高集積化に大きく貢献することができる。[Table] Example 4 For practical use, it is necessary to increase the size of the column and shorten the operation time, so as a guideline for increasing the size of the column, an industrial anion exchange resin Diaion SA10B was used for a column with an inner diameter of 70 mmφ. Use something filled with
The same procedure as in Example 1 was carried out. It was possible to process the alumina at a rate of 0.1 per minute without impairing the quality of the alumina obtained. This shows that it is possible to use a larger column. Moreover, the recovery yield of Al was almost 100%. (Effects of the Invention) As described above, according to the present invention, radioactive elements, especially radioactive elements such as U, Th, which exhibit alpha decay,
Since it is possible to easily and stably produce materials for IC ceramic substrates with extremely low concentrations, it will be able to greatly contribute to future high integration of ICs.
第１図は硝酸水溶液中における強塩基性陰イオ
ン交換樹脂に対するＵ，Thイオンの分配係数と
硝酸モル濃度との関係を示す図、第２図は過塩素
酸水溶液中における強塩基性陰イオン交換樹脂に
対するＵ，Thイオンの分配係数と過塩素酸モル
濃度との関係を示す図、第３図Ａは実験に用いた
カラムの液層および樹脂層の配設状態を示す模式
図、第３図ＢはAl，Mg，Ca，ZrからＵ，Thを
分離するためのクロマトグラフ、第４図は本発明
方法の製造過程説明図である。
Figure 1 shows the relationship between the distribution coefficients of U and Th ions for strongly basic anion exchange resins in a nitric acid aqueous solution and the nitric acid molar concentration, and Figure 2 shows the relationship between the strong basic anion exchange resin in a perchloric acid aqueous solution. A diagram showing the relationship between the distribution coefficient of U and Th ions to resin and the molar concentration of perchlorate, Figure 3 A is a schematic diagram showing the arrangement of the liquid layer and resin layer of the column used in the experiment, Figure 3 B is a chromatograph for separating U and Th from Al, Mg, Ca, and Zr, and FIG. 4 is an illustration of the manufacturing process of the method of the present invention.
Claims (1)
またはAl化合物を主体とし、残部Mg，Ca，Zn
のなかから選ばれるいずれか少なくとも１種を含
む化合物からなるセラミツク原料を、硝酸、過塩
素酸モル濃度がそれぞれ１〜14M，0.1〜12Mで
ある硝酸および／または過塩素酸あるいはそれら
を主体とした混酸水溶液中に溶解させた後、この
水溶液を強塩基性陰イオン交換樹脂と２回以上接
触させることにより、前記原料の前記水溶液中に
溶出したＵおよびThを前記樹脂に吸着させた後、
前記水溶液からＵおよびThの濃度が1.5ppb以下
である酸化物を製造することを特徴とする放射性
元素濃度の極めて低いICセラミツク基板用材料
の製造方法。 ２ 前記混酸は硝酸と過塩素酸の全濃度範囲の混
酸、あるいは硝酸、過塩素酸のいずれか少なくと
も１種に下記(a)−(d)に示す酸を、硝酸、過塩素酸
のいずれか少なくとも一種の酸濃度の50％を超え
ない範囲で加えたものであることを特徴とする特
許請求の範囲第１項記載の方法。 (a)塩酸、(b)硫酸、(c)酢酸、(d)フツ化水素酸[Claims] 1. Al compound as material for IC ceramic substrate,
Or mainly composed of Al compounds, with the remainder being Mg, Ca, and Zn.
A ceramic raw material consisting of a compound containing at least one selected from the following, nitric acid and perchloric acid with a molar concentration of 1 to 14 M and 0.1 to 12 M, respectively, or nitric acid and/or perchloric acid as the main component. After dissolving in a mixed acid aqueous solution, this aqueous solution is brought into contact with a strongly basic anion exchange resin two or more times, so that U and Th eluted in the aqueous solution of the raw material are adsorbed on the resin,
A method for producing an IC ceramic substrate material having an extremely low radioactive element concentration, the method comprising producing an oxide having a U and Th concentration of 1.5 ppb or less from the aqueous solution. 2 The mixed acid is a mixed acid of nitric acid and perchloric acid in the entire concentration range, or a combination of at least one of nitric acid and perchloric acid with the acids shown in (a) to (d) below, and either nitric acid or perchloric acid. The method according to claim 1, characterized in that at least one acid is added in an amount not exceeding 50% of the concentration. (a) Hydrochloric acid, (b) sulfuric acid, (c) acetic acid, (d) hydrofluoric acid
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61094761A JPS62265161A (en) | 1986-04-25 | 1986-04-25 | Manufacture of mateial for ic ceramic substrate with extremely low radioactive element concentration |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61094761A JPS62265161A (en) | 1986-04-25 | 1986-04-25 | Manufacture of mateial for ic ceramic substrate with extremely low radioactive element concentration |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62265161A JPS62265161A (en) | 1987-11-18 |
| JPH0449502B2 true JPH0449502B2 (en) | 1992-08-11 |
Family
ID=14119082
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61094761A Granted JPS62265161A (en) | 1986-04-25 | 1986-04-25 | Manufacture of mateial for ic ceramic substrate with extremely low radioactive element concentration |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62265161A (en) |
-
1986
- 1986-04-25 JP JP61094761A patent/JPS62265161A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62265161A (en) | 1987-11-18 |
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