JPS6247955B2 - - Google Patents
Info
- Publication number
- JPS6247955B2 JPS6247955B2 JP17219182A JP17219182A JPS6247955B2 JP S6247955 B2 JPS6247955 B2 JP S6247955B2 JP 17219182 A JP17219182 A JP 17219182A JP 17219182 A JP17219182 A JP 17219182A JP S6247955 B2 JPS6247955 B2 JP S6247955B2
- Authority
- JP
- Japan
- Prior art keywords
- lead
- radioactive
- particles
- sulfamic acid
- less
- 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
Links
- 230000002285 radioactive effect Effects 0.000 claims description 19
- LNOPIUAQISRISI-UHFFFAOYSA-N n'-hydroxy-2-propan-2-ylsulfonylethanimidamide Chemical compound CC(C)S(=O)(=O)CC(N)=NO LNOPIUAQISRISI-UHFFFAOYSA-N 0.000 claims description 13
- 239000002245 particle Substances 0.000 claims description 11
- 238000005219 brazing Methods 0.000 claims description 8
- 239000007788 liquid Substances 0.000 claims description 8
- 238000000034 method Methods 0.000 claims description 6
- 238000007670 refining Methods 0.000 claims description 6
- 239000004065 semiconductor Substances 0.000 claims description 6
- 239000000945 filler Substances 0.000 claims description 5
- 239000002184 metal Substances 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 claims description 5
- 238000005304 joining Methods 0.000 claims description 3
- 238000005868 electrolysis reaction Methods 0.000 description 6
- LBDSXVIYZYSRII-IGMARMGPSA-N alpha-particle Chemical compound [4He+2] LBDSXVIYZYSRII-IGMARMGPSA-N 0.000 description 5
- 239000003792 electrolyte Substances 0.000 description 5
- 239000008151 electrolyte solution Substances 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 239000012776 electronic material Substances 0.000 description 4
- 239000011521 glass Substances 0.000 description 4
- 239000002253 acid Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000015654 memory Effects 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000010992 reflux Methods 0.000 description 2
- 229910052776 Thorium Inorganic materials 0.000 description 1
- 229910052770 Uranium Inorganic materials 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910000679 solder Inorganic materials 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- IIACRCGMVDHOTQ-UHFFFAOYSA-M sulfamate Chemical compound NS([O-])(=O)=O IIACRCGMVDHOTQ-UHFFFAOYSA-M 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
Landscapes
- Electrolytic Production Of Metals (AREA)
- Die Bonding (AREA)
Description
本発明は各種の電子材料向けに適した放射性α
粒子カウント数の低い鉛及びその電解精製方法に
関する。
近年電子材料向けとしての鉛の用途が拡大しつ
つあり、例えばICは勿論のこと、大容量メモリ
ー素子である64KRAM等のメモリーや各種超LSI
等の半導体装置のアツセンブリーに際し、装置部
材接合用のろう材として、特にダイボンデイング
用には鉛べ―スの合金が一部使用されているのを
はじめ、サーデイーブと呼ばれるパツケージの封
止には軟化点を下げ線膨張係数を調整するために
大量のPbOを添加した低融点ガラス、主として
PbO―B2O3系ガラスが使用されている。
一方、従来市販されている鉛には放射性同位元
素、特にＵ、Thの含有量が多く、従つてα粒子
のカウント数が３〜100CPH／cm2と高く、この影
響によつてメモリーのソフトエラーが惹起される
ため、その用途は限定されざるを得ず、例えばセ
ラミツクパツケージIC及びLSI蓋接合用ろう材
（現在80％Au―20％Snハンダが主として使用され
ている）としてはα粒子の影響がダイボンデイン
グの場合よりも直接的かつ大であるため、信頼性
の点から鉛ベースのろう材はこれまで用いられて
いない実状にある。
また、市販されている低融点ガラスのα粒子カ
ウント数を測定してみると、低α低融点ガラスと
言われているものでも、1CPH／cm2以上であり、
必ずしも満足できるものでないことが判明した。
また、粗鉛（Pb品位97.0〜99.5％）の工業的な
電解精製としては従来電解液に珪弗化水素酸を用
いる所謂ベツツ法が採用されているに過ぎなかつ
た。
本発明者らは以上の点を考慮し、上記の電子材
料向けに適する放射性α粒子カウント数が低い鉛
を製造すべく、鋭意研究を重ねた結果、４ナイン
以上の品位を有する鉛をアノードとしてスルフア
ミン酸浴で電解精製することによつて目的を達成
できることを見出し、本発明に到達した。すなわ
ち、本発明の要旨とするところは、
(1) 品位４ナイン以上で放射性同位元素の含有量
が50ppb未満であり、かつ放射性α粒子カウン
ト数が0.5CPH／cm2以下であることを特徴とす
る放射性α粒子カウント数の低い、半導体装置
部材接合用ろう材向けの鉛、
(2) 品位４ナイン以上の鉛をアノードとし、
Pb：30〜150ｇ／、放射性同位元素をほとん
ど含有しないスルフアミン酸液：30〜150ｇ／
の液組成でカソード電流密度：0.5〜
2.0Amp／ｄm2、液温度：15〜50℃の電解条件
で電解することを特徴とする放射性α粒子カウ
ント数の低い、半導体装置部材接合用ろう材向
けの鉛の製造方法、にある。
本発明で電解液として使用するスルフアミン酸
は放射性同位元素をほとんど含有しない市販品で
よく、４ナイン以上の品位を有する鉛をアノード
とし、上記市販のスルフアミン酸を電解液として
電解精製することによつて、アノード中に含まれ
ている放射性同位元素が電解精製されて、実施例
で示すように、放射性同位元素の含有量が50ppb
未満でかつ放射性α粒子のカウント数が
0.5CPH／cm2以下である放射性α粒子カウント数
の低い、半導体装置部材接合用ろう材向けの鉛が
得られる。
本発明における電解は品位４ナイン以上の鉛を
アノードとし、液組成および電解条件は次の通り
である。
液組成 Pb：30〜150ｇ／
スルフアミン酸：30〜150ｇ／
電解条件 カソード電流密度：0.5〜
2.0Amp／ｄm2
液温度：15〜50℃
ここで、上記の液組成及び電解条件の数値限定
の理由について述べる。
(a) 液組成
(イ) Pb：30〜150ｇ／
Pb濃度が30ｇ／未満ではPb以外の他の
元素も同時に析出してくるため、不純物の混
入となる。また150ｇ／を越えると、電解
液中に存在するPb量が多いために電解工程
の仕掛りとしてのPb量が多く、経済性が悪
い。
(ロ) スルフアミン酸：30〜150ｇ／
電解液中のスルフアミン酸濃度が30ｇ／
未満ではPbが電解液中にスムーズに溶け込
みにくく、また150ｇ／を越えると、スル
フアミン酸が多く不経過であるとともにスル
フアミン酸の結晶析出が生じる。
(b) 電解条件
(イ) カソード電流密度：0.5〜2.0Amp／ｄm2
電流密度が0.5Amp／ｄm2未満では電解時
間が長くかかりすぎ、また2.0Amp／ｄm2を
越えると、Pb以外の元素も析出し、不純物
の混入となる。
(ロ) 電解温度：15〜50℃
電解温度が15℃未満では、電解液の電気的
抵抗が大きく、電解効率が低い。また50℃を
越えると、電解液の蒸発によるロスが大きく
なる。
本発明の１実施例の装置系統図を図に示す。
図において、電解槽１に品位４ナイン以上の鉛
アノード２及び不溶解性カソード板３を挿入し、
環流ポンプ４でスルフアミン酸電解液７を熱交換
器５を通して環流させ、直流電源装置６により通
電し電解を行うものである。本発明は以上のごと
く、電子材料向けのPbの電解精製法として極め
て有用であり、その工業的価値は高いものであ
る。
次に、本発明を実施例によつてさらに具体的に
説明する。
実施例
上記の電解条件でスルフアミン酸浴より得られ
たPbカソード中の放射性同位元素の濃度及び放
射性α粒子カウント数の測定結果を実施例１〜４
として次表に示す。
なお、比較のために通常の電解精製法である珪
弗化水素酸より得られたPbカソード中の数値を
次表に比較例１〜４として併せ示す。
The present invention is a radioactive α suitable for various electronic materials.
This invention relates to lead with a low particle count and an electrolytic refining method thereof. In recent years, the use of lead in electronic materials has been expanding, including not only ICs but also memories such as 64KRAM, which is a large capacity memory element, and various ultra-LSIs.
When assembling semiconductor devices such as these, some lead-based alloys are used as brazing materials for joining device parts, especially for die bonding. Low melting point glass with a large amount of PbO added to lower the point and adjust the coefficient of linear expansion, mainly
PbO―B 2 O 3 glass is used. On the other hand, conventionally commercially available lead has a high content of radioactive isotopes, especially U and Th, and therefore has a high alpha particle count of 3 to 100 CPH/ cm2 , which can cause memory soft errors. For example, as a brazing material for joining ceramic package ICs and LSI lids (currently 80% Au-20% Sn solder is mainly used), its use is limited due to the effects of α particles. Lead-based brazing materials have not been used to date because of their reliability, which is more direct and larger than in die bonding. In addition, when we measured the α particle count of commercially available low melting point glasses, we found that even what is said to be low α low melting point glass had a count of 1 CPH/cm 2 or more.
It turned out that this was not always satisfactory. Furthermore, for industrial electrolytic refining of crude lead (Pb grade 97.0 to 99.5%), only the so-called Betts method, which uses hydrosilicofluoric acid as an electrolytic solution, has conventionally been adopted. Taking the above points into consideration, the inventors of the present invention have conducted extensive research to produce lead with a low radioactive alpha particle count that is suitable for the above-mentioned electronic materials. It was discovered that the object could be achieved by electrolytic refining in a sulfamic acid bath, and the present invention was achieved. That is, the gist of the present invention is as follows: (1) The product is characterized by having a quality of 4 nines or more, a radioactive isotope content of less than 50 ppb, and a radioactive α particle count of 0.5 CPH/cm 2 or less. (2) Lead with a grade of 4 nines or higher as an anode, which has a low radioactive alpha particle count and is used as a brazing filler metal for bonding semiconductor device parts;
Pb: 30-150g/, sulfamic acid solution containing almost no radioactive isotopes: 30-150g/
Cathode current density with liquid composition: 0.5~
A method for producing lead for use as a brazing filler metal for bonding semiconductor device parts, which has a low count of radioactive α particles and is characterized by electrolyzing under electrolytic conditions of 2.0 Amp/dm 2 and a liquid temperature of 15 to 50°C. The sulfamic acid used as the electrolyte in the present invention may be a commercially available product containing almost no radioactive isotope, and can be electrolytically purified using lead having a grade of 4 nines or higher as an anode and the commercially available sulfamic acid used as the electrolyte. Then, the radioactive isotope contained in the anode is electrolytically refined, and as shown in the example, the radioactive isotope content is 50 ppb.
and the number of counts of radioactive alpha particles is less than
Lead for use as a brazing filler metal for bonding semiconductor device parts can be obtained with a low radioactive α particle count of 0.5 CPH/cm 2 or less. In the electrolysis in the present invention, lead of grade 4 nines or higher is used as an anode, and the liquid composition and electrolytic conditions are as follows. Liquid composition Pb: 30-150g/ Sulfamic acid: 30-150g/ Electrolytic conditions Cathode current density: 0.5-
2.0 Amp/dm 2 liquid temperature: 15 to 50°C Here, the reason for the numerical limitations on the liquid composition and electrolytic conditions described above will be described. (a) Liquid composition (a) Pb: 30 to 150 g/ If the Pb concentration is less than 30 g/, other elements other than Pb will also precipitate, resulting in contamination of impurities. Moreover, if it exceeds 150g/, the amount of Pb present in the electrolytic solution is large, resulting in a large amount of Pb as a starting material in the electrolytic process, which is uneconomical. (b) Sulfamic acid: 30 to 150g/ Sulfamic acid concentration in electrolyte is 30g/
If the amount is less than 150 g/L, it is difficult for Pb to dissolve smoothly into the electrolytic solution, and if it exceeds 150 g/L, a large amount of sulfamic acid will not pass, and sulfamic acid crystals will precipitate. (b) Electrolysis conditions (a) Cathode current density: 0.5 to 2.0 Amp/dm 2 If the current density is less than 0.5 Amp/dm 2 , the electrolysis time will be too long, and if it exceeds 2.0 Amp/dm 2 , elements other than Pb will be removed. Also precipitates, resulting in contamination of impurities. (b) Electrolysis temperature: 15 to 50°C When the electrolysis temperature is less than 15°C, the electrical resistance of the electrolytic solution is large and the electrolytic efficiency is low. Furthermore, if the temperature exceeds 50°C, loss due to evaporation of the electrolyte increases. A system diagram of an apparatus according to an embodiment of the present invention is shown in the figure. In the figure, a lead anode 2 with a quality of 4 nines or more and an insoluble cathode plate 3 are inserted into an electrolytic cell 1,
A reflux pump 4 circulates the sulfamic acid electrolyte 7 through a heat exchanger 5, and a DC power supply 6 supplies electricity to perform electrolysis. As described above, the present invention is extremely useful as a method for electrolytically refining Pb for electronic materials, and its industrial value is high. Next, the present invention will be explained in more detail with reference to Examples. Examples Examples 1 to 4 are the measurement results of the radioisotope concentration and radioactive α particle count in the Pb cathode obtained from the sulfamic acid bath under the above electrolytic conditions.
as shown in the table below. For comparison, the values in the Pb cathode obtained from hydrosilicofluoric acid, which is a common electrolytic refining method, are also shown in the following table as Comparative Examples 1 to 4.
【表】
上表から明らかであるように、実施例によつて
得られたPbカソードはアノードに比較して、放
射性同位元素の含有濃度が大幅に低下するととも
に放射性α粒子カウント数も減少しており、効果
が大であることが確認した。なお、本発明におい
ては鉛はスルフアミン酸鉛として存在する。
比較例ではアノードに比し、カソードの方が放
射性同位元素の濃度及びα粒子のカウント数とも
に上昇しているが、これは市販の珪弗化水素酸中
には放射性同位元素、特にThの含有量が高いこ
とによるものと考えられる。[Table] As is clear from the above table, the Pb cathode obtained in the example has a significantly lower radioisotope content concentration and a lower number of radioactive α particle counts than the anode. It was confirmed that the effect was large. In the present invention, lead exists as lead sulfamate. In the comparative example, the concentration of radioactive isotopes and the count number of α particles are higher at the cathode than at the anode, but this is because commercially available hydrofluorosilicic acid contains radioisotopes, especially Th. This is thought to be due to the high amount.
図面は本発明の１実施例の装置系統図である。
図において、
１…電解槽、２…鉛アノード、３…不溶解性カ
ソード板、４…環流ポンプ、５…熱交換器、６…
直流電源装置、７…スルフアミン酸電解液。
The drawing is a system diagram of an apparatus according to an embodiment of the present invention.
In the figure, 1...electrolytic cell, 2...lead anode, 3...insoluble cathode plate, 4...reflux pump, 5...heat exchanger, 6...
DC power supply device, 7...Sulfamic acid electrolyte solution.
Claims (1)
の含有量が50ppb未満でかつ放射性α粒子のカウ
ント数が0.5CPH／cm2以下であることを特徴とす
る放射性α粒子カウント数の低い、半導体装置部
材接合用ろう材向けの鉛。 ２ 品位４ナイン以上の鉛をアノードとし、
Pb：30〜150ｇ／、放射性同位元素をほとんど
含有しないスルフアミン酸液：30〜150ｇ／の
液組成でカソード電流密度：0.5〜2.0Amp／ｄ
m2、液温度：15〜50℃の電解条件で電解すること
を特徴とする放射性α粒子カウント数の低い、半
導体装置部材接合用ろう材向けの鉛の電解精製方
法。[Claims] Radioactive α particles having a quality of 1.4 nines or more, containing a radioisotope content of less than 50 ppb, and having a count number of radioactive α particles of 0.5 CPH/cm 2 or less. Lead with low count for brazing filler metal for joining semiconductor device parts. 2. Use lead of grade 4 nines or higher as an anode,
Pb: 30-150g/, sulfamic acid solution containing almost no radioisotope: 30-150g/, cathode current density: 0.5-2.0Amp/d
m 2 , liquid temperature: 15 to 50° C. A lead electrolytic refining method for use as a brazing filler metal for bonding semiconductor device parts, which has a low count of radioactive α particles.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17219182A JPS5964791A (en) | 1982-09-30 | 1982-09-30 | Lead with low count number of radioactive alpha particle and electrolytic purification thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17219182A JPS5964791A (en) | 1982-09-30 | 1982-09-30 | Lead with low count number of radioactive alpha particle and electrolytic purification thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5964791A JPS5964791A (en) | 1984-04-12 |
| JPS6247955B2 true JPS6247955B2 (en) | 1987-10-12 |
Family
ID=15937258
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17219182A Granted JPS5964791A (en) | 1982-09-30 | 1982-09-30 | Lead with low count number of radioactive alpha particle and electrolytic purification thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5964791A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007004394A1 (en) | 2005-07-01 | 2007-01-11 | Nippon Mining & Metals Co., Ltd. | High-purity tin or tin alloy and process for producing high-purity tin |
| WO2011114824A1 (en) | 2010-03-16 | 2011-09-22 | Jx日鉱日石金属株式会社 | Low α-dose tin or tin alloy and method for producing same |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU2003272790A1 (en) | 2002-10-08 | 2004-05-04 | Honeywell International Inc. | Semiconductor packages, lead-containing solders and anodes and methods of removing alpha-emitters from materials |
| CN103415633B (en) | 2011-03-07 | 2015-09-09 | 吉坤日矿日石金属株式会社 | The manufacture method of copper or copper alloy, bonding wire, the manufacture method of copper, the manufacture method of copper alloy and bonding wire |
| US8993978B2 (en) | 2012-05-04 | 2015-03-31 | Honeywell International Inc. | Method for assessing an alpha particle emission potential of A metallic material |
| EP2987892A1 (en) | 2014-02-20 | 2016-02-24 | JX Nippon Mining & Metals Corporation | Method for producing low -emitting bismuth and low -emitting bismuth |
| JP6453743B2 (en) * | 2014-12-03 | 2019-01-16 | Ｊｘ金属株式会社 | Method for electrolytic purification of lead using sulfamic acid bath |
| US10106904B2 (en) | 2014-12-03 | 2018-10-23 | Jx Nippon Mining & Metals Corporation | Method for electrolytically refining lead in sulfamate bath |
-
1982
- 1982-09-30 JP JP17219182A patent/JPS5964791A/en active Granted
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007004394A1 (en) | 2005-07-01 | 2007-01-11 | Nippon Mining & Metals Co., Ltd. | High-purity tin or tin alloy and process for producing high-purity tin |
| US9340850B2 (en) | 2005-07-01 | 2016-05-17 | Jx Nippon Mining & Metals Corporation | Process for producing high-purity tin |
| WO2011114824A1 (en) | 2010-03-16 | 2011-09-22 | Jx日鉱日石金属株式会社 | Low α-dose tin or tin alloy and method for producing same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5964791A (en) | 1984-04-12 |
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