JP2942688B2 - Method for analyzing trace elements in metals and semiconductors - Google Patents
Method for analyzing trace elements in metals and semiconductorsInfo
- Publication number
- JP2942688B2 JP2942688B2 JP5094583A JP9458393A JP2942688B2 JP 2942688 B2 JP2942688 B2 JP 2942688B2 JP 5094583 A JP5094583 A JP 5094583A JP 9458393 A JP9458393 A JP 9458393A JP 2942688 B2 JP2942688 B2 JP 2942688B2
- Authority
- JP
- Japan
- Prior art keywords
- concentration
- sample
- less
- heating
- trace elements
- 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
- 235000013619 trace mineral Nutrition 0.000 title claims description 27
- 239000011573 trace mineral Substances 0.000 title claims description 27
- 238000000034 method Methods 0.000 title claims description 26
- 229910052751 metal Inorganic materials 0.000 title claims description 20
- 239000002184 metal Substances 0.000 title claims description 20
- 239000004065 semiconductor Substances 0.000 title claims description 14
- 150000002739 metals Chemical class 0.000 title claims description 9
- 238000003887 surface segregation Methods 0.000 claims description 17
- 230000008018 melting Effects 0.000 claims description 9
- 238000002844 melting Methods 0.000 claims description 9
- 239000011159 matrix material Substances 0.000 claims description 4
- 238000001304 sample melting Methods 0.000 claims description 2
- 238000010438 heat treatment Methods 0.000 description 32
- 238000005259 measurement Methods 0.000 description 18
- 238000004458 analytical method Methods 0.000 description 14
- 238000011088 calibration curve Methods 0.000 description 12
- 239000000463 material Substances 0.000 description 9
- 238000009616 inductively coupled plasma Methods 0.000 description 8
- 239000007789 gas Substances 0.000 description 6
- 238000011002 quantification Methods 0.000 description 5
- 238000004445 quantitative analysis Methods 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 229910052698 phosphorus Inorganic materials 0.000 description 4
- 238000004677 spark ionization mass spectrometry Methods 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 229910052717 sulfur Inorganic materials 0.000 description 4
- 238000010894 electron beam technology Methods 0.000 description 3
- 238000004993 emission spectroscopy Methods 0.000 description 3
- 238000005498 polishing Methods 0.000 description 3
- 238000005204 segregation Methods 0.000 description 3
- 238000004544 sputter deposition Methods 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 238000000516 activation analysis Methods 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 229910052787 antimony Inorganic materials 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000001066 destructive effect Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 239000012776 electronic material Substances 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 229910052718 tin Inorganic materials 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 238000004876 x-ray fluorescence Methods 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 229910052790 beryllium Inorganic materials 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 239000012770 industrial material Substances 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 238000003947 neutron activation analysis Methods 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 238000001420 photoelectron spectroscopy Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 238000004451 qualitative analysis Methods 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000000682 scanning probe acoustic microscopy Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000005211 surface analysis Methods 0.000 description 1
- 239000013077 target material Substances 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
Landscapes
- Analysing Materials By The Use Of Radiation (AREA)
- Sampling And Sample Adjustment (AREA)
- Testing Or Measuring Of Semiconductors Or The Like (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、高純度金属ならびに半
導体材料中の微量元素の定量方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for determining high-purity metals and trace elements in semiconductor materials.
【０００２】[0002]
【従来の技術】高純度金属中の微量添加元素の定量方法
において、幾つかの方法が実用されている。すなわち、
原子吸光法、発光分光分析法、蛍光Ｘ線分析、高周波誘
導結合プラズマ発光分析法（ＩＣＰ発光分析法）などが
ある。いずれの場合においても、検出限界はppm 程度で
あり、１０ppm 以下の定量には精度の上で問題がある場
合が多い。また、特にＣ，Ｏ，Ｎ，Ｃｌ，Ｓなどの微量
元素を定量する場合には表面の汚染の影響を十分考慮す
る必要がある。更に原子吸光法、発光分光分析法、ＩＣ
Ｐ発光分析法においては、試料を非破壊状態で測定する
ことは困難である。また発光分光分析のうち、検出感度
が比較的高いグリムグロー放電法は、数mm径の平面を持
つ試料が必要であるなど、試料形状の制約も多い。蛍光
Ｘ線測定においては、Ｎａより軽い元素を測定するのは
難しい。2. Description of the Related Art Several methods have been put to practical use for quantifying trace added elements in high-purity metals. That is,
Atomic absorption, emission spectroscopy, X-ray fluorescence analysis, high frequency inductively coupled plasma emission analysis (ICP emission analysis), and the like. In any case, the detection limit is on the order of ppm, and the determination of 10 ppm or less often has a problem in accuracy. In particular, when quantifying trace elements such as C, O, N, Cl, and S, it is necessary to sufficiently consider the influence of surface contamination. Atomic absorption, emission spectroscopy, IC
In P emission analysis, it is difficult to measure a sample in a non-destructive state. Among emission spectroscopy, the Grim Glow Discharge method, which has a relatively high detection sensitivity, requires a sample having a plane with a diameter of several millimeters, and there are many restrictions on the sample shape. In fluorescent X-ray measurement, it is difficult to measure an element lighter than Na.
【０００３】定量下限を１ppm とする分析方法として
は、化学分析法、放射化分析、スパークソース質量分析
（ＳＳＭＳ）、２次イオン質量分析装置（ＳＩＭＳ）な
どが挙げられるが、化学分析法では、試料が比較的多量
に必要であること、また操作中の汚染、定量感度などの
点で問題がある。放射化分析法は最も高感度といえる
が、熱中性子放射化分析は原子炉を必要とするのであま
り一般的とはいえない。また、ＳＳＭＳ，ＳＩＭＳなど
も試料調整が困難で、また全ての元素が定量できるわけ
ではない。ＳＩＭＳはＳＳＭＳと比べて精度は良く、局
所分析には優れているが、逆に平均的な組成を求めるに
は問題がある。[0003] Analytical methods for setting the lower limit of quantification to 1 ppm include chemical analysis, activation analysis, spark source mass spectrometry (SSMS), and secondary ion mass spectrometer (SIMS). There are problems in that a relatively large amount of sample is required, contamination during the operation, and quantitative sensitivity. Activation analysis is the most sensitive, but thermal neutron activation analysis is less common because it requires a reactor. Further, it is difficult to prepare a sample for SSMS, SIMS and the like, and not all elements can be quantified. SIMS has higher accuracy and better local analysis than SSMS, but has a problem in obtaining an average composition.
【０００４】[0004]
【発明が解決しようとする課題】上述のように高純度金
属中の微量元素の定量方法は、１０ppm オーダー以下の
微量元素の定量化には種々の制約がある。特に、この種
の測定においては、試料形状に制約があり、蛍光Ｘ線分
析以外は非破壊で測定することは不可能である。金属材
料、半導体材料ともに、近年の材料の高機能化にともな
い、微量元素の高精度での制御がより重要となってき
た。たとえば、半導体素子の製造に用いられるＡｌ配線
膜や高融点金属などは通常スパッタ法により成膜される
が、そのターゲット材料はppm 以下の不純物量に制御さ
れ製造されている。またスパッタ中の残留ガス原子の取
り込みについても厳密な制御が必要である。また高性能
オーディオ機器の配線、ケーブルなどに使用される高純
度Ｃｕは、９９．９９９以上のものが使用されるように
なってきた。As described above, the method for quantifying trace elements in high-purity metals has various limitations in quantifying trace elements of the order of 10 ppm or less. In particular, in this type of measurement, the shape of the sample is limited, and it is impossible to perform nondestructive measurement other than X-ray fluorescence analysis. For both metal materials and semiconductor materials, high-precision control of trace elements has become more important as materials have become more sophisticated in recent years. For example, an Al wiring film, a high melting point metal, and the like used in the manufacture of a semiconductor element are usually formed by a sputtering method, and the target material is manufactured by controlling the impurity amount to less than ppm. Strict control is also required for the capture of residual gas atoms during sputtering. In addition, 99.999 or more high-purity Cu used for wiring and cables of high-performance audio equipment has come to be used.
【０００５】一方、半導体実装材料として使用されてい
る、ボンディングワイヤなどもその一例であり、破断強
度や伸びといったワイヤ特性を調節するために、高純度
金属（Ａｕ）に１００ppm 以下の微量元素たとえばＢ
ｅ，Ｃａなどを添加することによって用いられる。また
コンデンサー箔に使用されている、高純度アルミニウム
など、他の電子材料、半導体材料に関しても同様に高金
属中に微量元素を添加することによってその特性を制御
したり、逆に金属中に含まれる不純物が導電性や耐食性
などに悪影響を及ぼしたりする。[0005] On the other hand, a bonding wire used as a semiconductor mounting material is also an example. In order to adjust wire characteristics such as breaking strength and elongation, a high-purity metal (Au) contains a trace element of 100 ppm or less, such as B.
It is used by adding e, Ca and the like. Also for other electronic materials and semiconductor materials such as high-purity aluminum used for capacitor foil, the characteristics can be controlled by adding trace elements to high metals, or conversely included in metals. Impurities adversely affect conductivity, corrosion resistance, and the like.
【０００６】また鉄鋼材料においても近年は、Ｃ，Ｐ，
Ｓ，Ｎ，Ｂ，Ｏ，Ｈなどの元素の高精度での制御がより
重要になってきている。たとえば深絞り鋼では、Ｃを１
０ppm 程度に制御することでその特性が著しく向上し、
またＰ，Ｓｎ，Ｓｂは鉄鋼中で粒界に％オーダーで偏析
して粒界脆化をひきおこすことが知られているが、バル
ク中の濃度を１０ppm 程度以下に低減することにより、
低温靭性、耐水素脆性が改善される。In recent years, in steel materials, C, P,
It is becoming more important to control elements such as S, N, B, O, and H with high accuracy. For example, in deep drawn steel, C is 1
By controlling to about 0 ppm, the characteristics are remarkably improved,
It is known that P, Sn, and Sb segregate at the grain boundaries in steel in the order of% and cause grain boundary embrittlement. However, by reducing the concentration in the bulk to about 10 ppm or less,
Low temperature toughness and hydrogen embrittlement resistance are improved.
【０００７】本発明は、高純度金属中の微量元素を、pp
m オーダーの精度をもって定量化し、試料形状による制
約が少なく、同時に試料は非破壊で用いることができる
定量方法を提供するものである。According to the present invention, trace elements in high-purity metals are
The purpose of the present invention is to provide a quantification method in which quantification is performed with m-order accuracy, the sample shape is less restricted, and the sample can be used nondestructively.
【０００８】[0008]
【課題を解決するための手段および作用】本発明は鉄鋼
材料、工業用材料、電子材料、半導体材料など中に１０
ppm オーダー以下で存在する、特に材料特性に影響の大
きい微量元素が、真空中で加熱されることによって表面
に％オーダーで偏析することに着目したものであり、表
面分析装置内の真空で試料を加熱することにより、微量
元素を表面に高濃度に偏析させ、その濃度を測定するこ
とにより、逆にバルク中の微量元素の濃度を決定する定
量法である。SUMMARY OF THE INVENTION The present invention relates to a steel material, an industrial material, an electronic material, a semiconductor material and the like.
It focuses on the fact that trace elements that exist in the order of ppm or less, and particularly have a significant effect on material properties, segregate on the surface in% order when heated in vacuum. This is a quantitative method in which a trace element is segregated to a high concentration on the surface by heating and the concentration of the trace element in the bulk is determined by measuring the concentration.
【０００９】以下に本発明を詳細に説明する。微量元素
の制御が重要なこのような元素のほとんどは、その含有
量は微量にもかかわらず、粒界や表面に偏析しやすいと
いう特徴がある。すなわちバルク中ではppm 〜数１０pp
m であっても、特定の加熱条件では表面に％オーダー存
在することが多い。またバルク中の濃度と表面濃度との
関係は加熱条件すなわち温度、時間、試料表面状態で同
一で、かつ加熱雰囲気が高真空中であれば一定である。
したがってその関係をあらかじめ決定して検量線を作成
しておけば、表面濃度の測定により、バルク濃度の決定
が可能となる。Hereinafter, the present invention will be described in detail. Most of these elements, for which control of trace elements is important, have a feature that they are easily segregated at grain boundaries and surfaces, even though their contents are very small. That is, ppm to several tens of pp in bulk
Even if m 2, it often exists on the surface in% order under specific heating conditions. The relationship between the concentration in the bulk and the surface concentration is the same under the heating conditions, that is, the temperature, time, and surface condition of the sample, and is constant when the heating atmosphere is in a high vacuum.
Therefore, if the relationship is determined in advance and a calibration curve is created, the bulk concentration can be determined by measuring the surface concentration.
【００１０】すなわち、本発明は表面を清浄に仕上げた
金属、または半導体を１０-7Torr以下の高真空の表面分
析装置内で一定温度に加熱して、異種元素の表面偏析濃
度を測定することにより、金属中及び半導体に含まれる
異種元素濃度を定量する微量元素定量法であり、特に固
溶限が小さい場合には、微量元素の濃度範囲としては含
有量がその元素の最大固溶量以下であることが好まし
い。また表面に偏析して高濃度化するのはマトリックス
金属と微量元素の原子半径の比が０．９以下１．１以上
で顕著となるので、検出感度が上がり好ましい。具体例
としては、マトリックス金属として、Ｃｕ，Ａｕ，Ａ
ｌ，Ａｇ，Ｆｅ，Ｓｉ，Ｎｉ，Ｔｉ，Ｐｔ，Ｃｏ，Ｐ
ｄ，Ｗなどが挙げられ、微量元素としては、Ｂ，Ｃ，
Ｎ，Ｏなどのガス元素、Ｌｉ，Ｂｅ，Ａｌ，Ｐ，Ｓ，Ｃ
ａ，Ｔｉ，Ｍｎ，Ｐｄ，Ａｕ，Ａｇ，Ｉｎ，Ｓｎ，Ｓ
ｉ，Ｓｂ，Ｍｏ，Ｆｅなどの元素、また、アルカリ金
属、遷移金属などの定量にも適用できる。That is, according to the present invention, a metal or semiconductor whose surface is finished clean is heated to a constant temperature in a high vacuum surface analyzer of 10 -7 Torr or less to measure the surface segregation concentration of different elements. This is a trace element determination method that determines the concentration of different elements contained in metals and semiconductors. Particularly when the solid solubility limit is small, the content of the trace element is not more than the maximum solid solution amount of the element. It is preferred that In addition, segregation on the surface to increase the concentration becomes remarkable when the ratio of the atomic radius of the matrix metal to the trace element is 0.9 or less and 1.1 or more. As a specific example, Cu, Au, A
1, Ag, Fe, Si, Ni, Ti, Pt, Co, P
d, W, etc., and the trace elements include B, C,
Gas elements such as N and O, Li, Be, Al, P, S, C
a, Ti, Mn, Pd, Au, Ag, In, Sn, S
It can be applied to the determination of elements such as i, Sb, Mo, and Fe, and alkali metals and transition metals.
【００１１】表面分析法としてはオージェ電子分光法
（ＡＥＳ法）、光電子分光法（ＸＰＳ法）などを用いる
ことができる。加熱装置としては、分析装置の真空チャ
ンバー内もしくは、高真空分析チャンバーに連結し、高
真空を維持したまま分析室に試料を移動できる構造の高
真空チャンバー内に、加熱ステージを設置する。加熱が
高真空でない場合あるいは加熱後分析までの間に、ガス
雰囲気中にさらされると、偏析元素がガス元素と反応し
てバルク濃度と表面濃度の関係が一定でなくなったり、
表面へのガス原子の吸着で表面偏析濃度を測定すること
が困難となる。加熱機構としては、電子ビーム、電熱
線、ランプ加熱などを用いる方法が挙げられるが、電子
ビームのエネルギーがオージェ電子の低エネルギー領域
に影響を及ぼすことがあるので、電熱線、ランプ加熱な
どの機構を用いるのが望ましい。As a surface analysis method, Auger electron spectroscopy (AES method), photoelectron spectroscopy (XPS method) or the like can be used. As a heating device, a heating stage is installed in a vacuum chamber of the analyzer or in a high vacuum chamber connected to the high vacuum analysis chamber and capable of moving a sample to the analysis chamber while maintaining a high vacuum. If the heating is not in a high vacuum or if it is exposed to a gas atmosphere before the analysis after the heating, the segregated elements will react with the gas elements and the relationship between the bulk concentration and the surface concentration will not be constant,
It becomes difficult to measure the surface segregation concentration due to adsorption of gas atoms on the surface. Examples of the heating mechanism include a method using an electron beam, a heating wire, and lamp heating. However, since the energy of the electron beam may affect a low energy region of Auger electrons, a mechanism such as a heating wire or a lamp heating is used. It is desirable to use
【００１２】試料は、ディスク状に切り出し、効率良く
加熱するために、裏面は試料ホルダーに密着するように
平面研磨することが好ましい。測定面である表面は表面
凹凸が強度ピークに及ぼす影響を取り除くために鏡面研
磨し、更に研磨歪を取り除くために約１μｍ程エッチン
グを施し、次に加工歪みを取り除くために、１０-3Torr
以下の真空中で十分に焼鈍することが好ましい。焼鈍加
熱温度は融点の１／２以上且つ４／５以下の温度が好ま
しい。融点の１／２以下では、研磨歪を十分にとること
が困難で、また４／５以上では、試料表面の蒸発によ
り、成分が変化する可能性がある。It is preferable that the sample is cut into a disk shape and the back surface is polished to be in close contact with the sample holder for efficient heating. The surface, which is the measurement surface, is mirror-polished to remove the influence of surface irregularities on the intensity peak, and further etched to about 1 μm to remove polishing strain, and then 10 −3 Torr to remove processing strain.
It is preferable to sufficiently anneal in the following vacuum. The annealing heating temperature is preferably not less than 1/2 and not more than 4/5 of the melting point. If the melting point is less than の, it is difficult to obtain sufficient polishing strain. If the melting point is more than 成分, the components may change due to evaporation of the sample surface.
【００１３】このように調整した試料を、加熱ステージ
に取り付け、まず表面上に付着している不純物や酸化物
を除去し表面を清浄にするために、イオンスパッタリン
グを施す。次に真空中で加熱を行いながら、もしくは加
熱後急冷して常温で表面に偏析した微量原子濃度を測定
する。The sample thus prepared is mounted on a heating stage, and is subjected to ion sputtering in order to remove impurities and oxides adhering to the surface and clean the surface. Next, the concentration of the trace atoms segregated on the surface is measured at room temperature while heating or quenching after heating in vacuum.
【００１４】測定時の真空度は、チャンバー内の残留ガ
スが表面へ吸着し、微量元素の偏析のバランスを変化さ
せるのを防ぐために、１０-7Torr以下に保持することが
好ましい。一定条件の試料加熱を測定チャンバーに連結
した真空チャンバーで行い、高真空を維持したまま測定
室に移動させ、常温で測定を行うこともできる。加熱温
度の範囲は、試料融点（絶対温度）の１／４かつ５０℃
（３２３Ｋ）以上で、融点の４／５以下が好ましい。マ
トリックス金属の融点の１／４以下では、表面に微量元
素が拡散して濃化するのに非常に長時間を要し実際的で
ない。また融点の１／４以上で、かつ拡散して表面に十
分濃化する場合でも、その温度が５０℃以下であると、
室温で保持した場合の拡散が無視できなくなり、測定精
度に問題を生じる可能性が高い。また試料の融点４／５
以上では試料が揮発し、チャンバー内を汚染する恐れが
ある。加熱保持時間は微量元素の表面偏析濃度が平衡に
達するに十分な時間が望ましい。測定面積は特定結晶方
位からの表面偏析エネルギーへの影響を無視できるよう
に、結晶粒の大きさより十分に大きい範囲を用いる。The degree of vacuum at the time of measurement is preferably maintained at 10 -7 Torr or less in order to prevent the residual gas in the chamber from adsorbing on the surface and changing the balance of segregation of trace elements. The sample can be heated under a constant condition in a vacuum chamber connected to the measurement chamber, moved to the measurement chamber while maintaining a high vacuum, and measured at room temperature. The heating temperature range is 1/4 of the sample melting point (absolute temperature) and 50 ° C.
(323K) or more and preferably 4/5 or less of the melting point. If the melting point of the matrix metal is 1/4 or less, it takes a very long time for the trace elements to diffuse and concentrate on the surface, which is not practical. Further, even when the temperature is not less than 1/4 of the melting point and is sufficiently concentrated on the surface by diffusion, if the temperature is 50 ° C. or less,
Diffusion when kept at room temperature cannot be ignored, and there is a high possibility that a problem will occur in measurement accuracy. The melting point of the sample is 4/5.
In this case, the sample may volatilize and contaminate the inside of the chamber. The heating and holding time is desirably a time sufficient for the surface segregation concentration of the trace element to reach equilibrium. The measurement area is set to a range sufficiently larger than the crystal grain size so that the influence of the specific crystal orientation on the surface segregation energy can be ignored.
【００１５】つぎに本発明による、表面濃度の時間変化
のバルク濃度依存性から分析する具体的方法について説
明する。表面偏析濃度Ｘｓ′はある一定温度で加熱され
たときの加熱初期には Ｘｓ′＝Ｂ Ｘｂ ｔ1/2 （２） で表わされる（図１）。Next, a specific method according to the present invention for analyzing the change in surface concentration with time in terms of the bulk concentration will be described. The surface segregation concentration Xs 'is expressed as Xs' = B Xb t 1/2 (2) at the beginning of heating when heated at a certain temperature (FIG. 1).
【００１６】Ｂはマトリックス金属と微量元素、加熱温
度で決定される定数、ｔは加熱時間である。あらかじめ
バルク濃度が既知の試料を準備し、ｔ1/2 とＸｓ′の直
線関係からＢを求めておけば、未知の試料のＸｓ′とｔ
1/2 の関係を測定し、バルク濃度Ｘｂを求めることがで
きる。更に好ましい方法としてはバルク濃度が異なる既
知の標準試料を３種類以上準備し、一定温度に加熱して
Ｘｓ′を各時間で測定しｔ1/2 に対する直線の傾きＢと
Ｘｂの関係を検量線（図２）として用いる。未知の試料
については同一温度に加熱してＸｓ′とｔ1/2 の直線の
傾きを求め、上記検量線を用いてバルク濃度Ｘｂを求め
る。次に実施例により詳細に説明する。B is a constant determined by the matrix metal and the trace element and the heating temperature, and t is the heating time. If a sample having a known bulk concentration is prepared in advance and B is determined from the linear relationship between t1 / 2 and Xs ', then Xs' and t
By measuring the relationship of 1/2 , the bulk concentration Xb can be obtained. As a more preferable method, three or more types of known standard samples having different bulk concentrations are prepared, heated to a constant temperature, Xs' is measured at each time, and the relationship between the gradient B and Xb of the straight line with respect to t1 / 2 is calibrated. (FIG. 2). The unknown sample is heated to the same temperature to determine the slope of the straight line between Xs' and t1 / 2 , and the bulk concentration Xb is determined using the above calibration curve. Next, an example will be described in detail.
【００１７】[0017]
〔実施例１〕９９．９９９％Ｎｉ中にＡｕを０．１at％
（０．０５wt．％）、０．２at％（０．０９wt．％）、
０．３at（０．１４wt．％）添加し、化学分析により、
それぞれの濃度の誤差が５％以内に納まっていることを
確認した試料を用いて、表面濃度の時間変化のバルク濃
度依存性からＮｉ中Ａｕの定量分析を行った。試料は直
径５mm、厚さ２mmに切り出し、表面を鏡面研磨した後、
加工歪みを取り除くために、７５０℃で４時間、真空中
（＜１０-7Torr）で焼鈍後、冷却（約３０Ｋ/min）し
た。オージェ電子分光装置は（ＡＱＭ ８０８）を用
い、電子線加速電圧５kV、試料電流値１μＡ、真空度５
×１０-9Torrで測定した。[Example 1] Au at 0.1 at% in 99.999% Ni
(0.05 wt.%), 0.2 at% (0.09 wt.%),
0.3at (0.14wt.%) Was added, and by chemical analysis,
Quantitative analysis of Au in Ni was performed from the sample whose concentration error was confirmed to be within 5%, based on the bulk concentration dependence of the change in surface concentration with time. The sample was cut out to a diameter of 5 mm and a thickness of 2 mm, and after mirror polishing the surface,
In order to remove the processing strain, it was annealed at 750 ° C. for 4 hours in a vacuum (<10 −7 Torr) and then cooled (about 30 K / min). An Auger electron spectrometer (AQM808) was used, and the electron beam acceleration voltage was 5 kV, the sample current value was 1 μA, and the degree of vacuum was 5
It was measured at × 10 −9 Torr.
【００１８】試料表面に偏析していたＯ及び、Ｃなどを
あらかじめＡｒ雰囲気中でスパッタしてクリーニングし
た後、ＡＥＳ内で６５０℃に保持し、６５０℃で加熱開
始時間から１０分置きに、計１１０分間、０〜２０００
eVのエネルギー範囲でスペクトルを測定した。得られた
結果を図３に示す。横軸に加熱保持時間の２乗根、縦軸
にＡＥＳ測定結果より得られた表面におけるＡｕ（６９
eV）ピーク、及びＮｉ（６１eV）ピークの高さの比Ｉ
（Ａｕ）／Ｉ（Ｎｉ）を示す。Ａｕピークとしては更に
横軸に各直線における傾きをとり、縦軸にバルク濃度を
プロットすると図４に示すような直線の検量線が得られ
た。After O and C segregated on the sample surface are sputtered and cleaned in an Ar atmosphere in advance, the sample is kept at 650 ° C. in the AES, and measured at 650 ° C. every 10 minutes from the heating start time. 110 minutes, 0-2000
The spectrum was measured in the energy range of eV. FIG. 3 shows the obtained results. The horizontal axis represents the square root of the heating holding time, and the vertical axis represents Au (69) on the surface obtained from the AES measurement result.
eV) Peak height ratio of Ni and 61 eV peak I
(Au) / I (Ni) is shown. As the Au peak, the inclination of each straight line is plotted on the horizontal axis, and the bulk concentration is plotted on the vertical axis, to obtain a linear calibration curve as shown in FIG.
【００１９】ＩＣＰ法により、あらかじめＡｕの濃度が
０．２at％と確認された試料を用いて、ＡＥＳ真空内に
おいて６５０℃で１０分間加熱を行い、Ａｕ（６９eV）
ピーク、及びＮｉ（６１eV）ピークの高さの比Ｉ（Ａ
ｕ）／Ｉ（Ｎｉ）を測定した。Ｉ（Ａｕ）／Ｉ（Ｎｉ）
＝０．０１３を得た。［｛Ｉ（Ａｕ）／Ｉ（Ｎｉ）｝／
（時間）1/2 ］＝５．３×１０-4となり、図４に示した
検量線から試料中のＡｕ濃度は、０．２at％であるとい
う結果が得られた。ＩＣＰ法による測定と比較して精度
良い一致が得られた。従って本法を用いてＮｉ中Ａｕの
微量定量を行った結果、精度良く測定可能なことが明ら
かとなった。Using a sample whose Au concentration was previously confirmed to be 0.2 at% by the ICP method, heating was performed at 650 ° C. for 10 minutes in an AES vacuum, and Au (69 eV) was used.
Ratio of peak height and Ni (61 eV) peak I (A
u) / I (Ni) was measured. I (Au) / I (Ni)
= 0.013. [{I (Au) / I (Ni)} /
(Time) 1/2 ] = 5.3 × 10 −4 , and the calibration curve shown in FIG. 4 showed that the Au concentration in the sample was 0.2 at%. Accurate matching was obtained as compared with the measurement by the ICP method. Therefore, as a result of performing a trace amount quantification of Au in Ni using this method, it became clear that measurement was possible with high accuracy.
【００２０】〔実施例２〕Ｃｕ中にＳｎを０．１at％、
０．２５at％、０．５at％、添加し、化学分析により、
それぞれの濃度の誤差が５％以内に納まっていることを
確認した試料を用いて、表面濃度の時間変化のバルク濃
度依存性からＣｕ中Ｓｎの定量分析を行った。試料はＡ
ＥＳ内で４００℃に保持し、４００℃で加熱開始時間か
ら２分置きに、計１０分間、Ｃｕピーク及びＳｎピーク
を測定した。得られた結果を図５に示す。横軸に加熱保
持時間の２乗根、縦軸にＡＥＳ測定結果より得られた表
面におけるＳｎ濃度を示す。更に横軸に各直線における
傾き［Ｓｎの表面偏析濃度／（加熱時間）1/2 ］をと
り、縦軸にバルク濃度をプロットすると図６に示すよう
な直線の検量線が得られた。Example 2 0.1 at% of Sn in Cu
0.25at%, 0.5at%, added, by chemical analysis,
Quantitative analysis of Sn in Cu was performed from a sample in which the error of each concentration was confirmed to be within 5%, based on the bulk concentration dependence of the time change of the surface concentration. The sample is A
The sample was kept at 400 ° C. in the ES, and the Cu peak and the Sn peak were measured at 400 ° C. every 2 minutes from the heating start time for a total of 10 minutes. The results obtained are shown in FIG. The horizontal axis shows the square root of the heating holding time, and the vertical axis shows the Sn concentration on the surface obtained from the AES measurement results. Further, the inclination [Sn surface segregation concentration / (heating time) 1/2 ] of each straight line is plotted on the horizontal axis, and the bulk concentration is plotted on the vertical axis, whereby a linear calibration curve as shown in FIG. 6 was obtained.
【００２１】ＩＣＰ法により、あらかじめＳｎの濃度が
０．３at％と確認された試料を用いて、ＡＥＳ真空内に
おいて４００℃で２分間加熱を行い、Ｓｎの表面偏析濃
度を測定した。表面偏析濃度は６．４０at％となった。
［Ｓｎの表面偏析濃度／（時間）1/2 ］を計算すると、
０．５８という値が得られ、図６に示した検量線から試
料中のＳｎ濃度は、０．３at％であるという結果が得ら
れた。ＩＣＰ法による測定結果と比較して同程度の結果
が得られた。従って本法を用いてＣｕ中Ｓｎの微量定量
を行った結果、精度よく測定可能なことが明らかとなっ
た。Using a sample in which the Sn concentration was previously confirmed to be 0.3 at% by the ICP method, the sample was heated in an AES vacuum at 400 ° C. for 2 minutes, and the surface segregation concentration of Sn was measured. The surface segregation concentration was 6.40 at%.
When [Sn surface segregation concentration / (time) 1/2 ] is calculated,
A value of 0.58 was obtained, and from the calibration curve shown in FIG. 6, a result was obtained that the Sn concentration in the sample was 0.3 at%. Comparable results were obtained as compared with the measurement results by the ICP method. Therefore, as a result of performing a trace amount quantification of Sn in Cu using this method, it became clear that accurate measurement was possible.
【００２２】〔実施例３〕Ｆｅ中にＰを０．１at％
（０．０６wt．％）、０．５at％（０．２８wt．％）、
１．０at（０．５５wt．％）添加し、化学分析により、
それぞれの濃度の誤差が５％以内に納まっていることを
確認した試料を用いて、表面濃度の時間変化のバルク濃
度依存性からＦｅ中Ｐの定量分析を行った。試料はＡＥ
Ｓ内で６００℃に保持し、６００℃で加熱開始時間から
５分置きに、計３０分間、０〜２０００ｅＶのエネルギ
ー範囲でスペクトルを測定した。得られた結果を図７に
示す。横軸に加熱保持時間の２乗根、縦軸にＡＥＳ測定
結果より得られた表面におけるＰ濃度を示す。更に横軸
に各直線における傾きをとり、縦軸にバルク濃度をプロ
ットすると図８に示すような直線の検量線が得られた。Example 3 0.1 at% of P in Fe
(0.06 wt.%), 0.5 at% (0.28 wt.%),
1.0at (0.55wt.%) Was added, and by chemical analysis,
Quantitative analysis of P in Fe was carried out from the samples in which the errors of the respective concentrations were confirmed to be within 5% from the bulk concentration dependence of the time change of the surface concentration. The sample is AE
The spectrum was measured at 600 [deg.] C. in S, every 5 minutes from the heating start time at 600 [deg.] C., for a total of 30 minutes in an energy range of 0 to 2000 eV. FIG. 7 shows the obtained results. The horizontal axis indicates the square root of the heating holding time, and the vertical axis indicates the P concentration on the surface obtained from the AES measurement result. Further, the inclination of each straight line is plotted on the horizontal axis, and the bulk concentration is plotted on the vertical axis, to obtain a linear calibration curve as shown in FIG.
【００２３】ＩＣＰ法により、あらかじめＳｎの濃度が
１．３at％と確認された試料を用いて、ＡＥＳ真空内に
おいて６００℃で５分、１０分、２０分間加熱を行い、
Ｐの表面偏析濃度を測定した。横軸に時間の２乗根、縦
軸に表面偏析濃度をプロットし得られた直線の傾き［Ｐ
の表面偏析濃度／（時間）1/2 ］を計算すると、１．３
２という値が得られ、図８に示した検量線から試料中の
Ｐ濃度は、１．２９at％であるという結果が得られた。
ＩＣＰ法による測定と比較して精度よい一致が得られ
た。従って本法を用いてＦｅ中のＰの微量定量を行った
結果、精度よく測定可能なことが明らかとなった。Using a sample whose Sn concentration was previously confirmed to be 1.3 at% by the ICP method, heating was performed at 600 ° C. for 5 minutes, 10 minutes, and 20 minutes in an AES vacuum.
The surface segregation concentration of P was measured. The horizontal axis of time is plotted on the horizontal axis, and the surface segregation concentration is plotted on the vertical axis.
Calculated from the surface segregation concentration / (time) 1/2 ]
A value of 2 was obtained, and the result that the P concentration in the sample was 1.29 at% was obtained from the calibration curve shown in FIG.
Accurate matching was obtained as compared with the measurement by the ICP method. Therefore, as a result of performing a trace amount determination of P in Fe using the present method, it became clear that measurement was possible with high accuracy.
【００２４】[0024]
【発明の効果】以上のように、本発明によれば、金属、
半導体中に含まれる微量濃度の不純物でも、表面に％オ
ーダーで偏析することを利用すれば、高精度且つ非破壊
な定量分析が可能なことが確認できた。また、本発明
は、微量元素の簡便な定性分析方法としても用いること
が可能である。As described above, according to the present invention, metal,
It has been confirmed that high-precision and non-destructive quantitative analysis can be performed by using segregation on the surface in the order of% even for a trace concentration of impurities contained in a semiconductor. Further, the present invention can also be used as a simple qualitative analysis method for trace elements.
【図１】表面偏析濃度の時間依存性を示す模式図であ
る。FIG. 1 is a schematic diagram showing the time dependency of the surface segregation concentration.
【図２】表面濃度の時間依存性からバルク濃度を求める
検量線である。FIG. 2 is a calibration curve for obtaining a bulk concentration from a time dependency of a surface concentration.
【図３】Ｎｉ中Ａｕの表面偏析濃度の時間依存性を示す
図である。FIG. 3 is a diagram showing the time dependence of the surface segregation concentration of Au in Ni.
【図４】Ｎｉ中Ａｕの表面濃度の時間依存性からバルク
濃度を求める検量線である。FIG. 4 is a calibration curve for obtaining a bulk concentration from a time dependency of a surface concentration of Au in Ni.
【図５】Ｃｕ中Ｓｎの表面偏析濃度の時間依存性を示す
図である。FIG. 5 is a diagram showing the time dependence of the surface segregation concentration of Sn in Cu.
【図６】Ｃｕ中Ｓｎの表面濃度の時間依存性からバルク
濃度を求める検量線である。FIG. 6 is a calibration curve for obtaining a bulk concentration from the time dependency of the surface concentration of Sn in Cu.
【図７】Ｆｅ中Ｐの表面偏析濃度の時間依存性を示す図
である。FIG. 7 is a diagram showing the time dependency of the surface segregation concentration of P in Fe.
【図８】Ｆｅ中Ｐの表面濃度の時間依存性からバルク濃
度を求める検量線である。FIG. 8 is a calibration curve for obtaining a bulk concentration from the time dependency of the surface concentration of P in Fe.
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.6，ＤＢ名) G01N 23/00 - 23/227 H01L 21/66 G01N 1/28 ＪＩＣＳＴファイル（ＪＯＩＳ)────────────────────────────────────────────────── ─── Continued on the front page (58) Field surveyed (Int. Cl. 6 , DB name) G01N 23/00-23/227 H01L 21/66 G01N 1/28 JICST file (JOIS)
Claims (3)
体を１０-7Torr以下の高真空の表面分析装置内で、試料
融点（絶対温度）の１／４かつ５０℃（３２３Ｋ）以
上、融点の４／５以下に加熱して、該金属または半導体
に微量に含有されている異種元素の表面偏析濃度を測定
し、表面濃度の時間変化のバルク濃度依存性から、金属
中及び半導体に含まれる微量異種元素濃度を定量する金
属、及び半導体中の微量元素分析方法。1. A metal or semiconductor whose surface has been cleaned is cleaned in a high vacuum surface analyzer of 10 -7 Torr or less at a temperature of １ ／ of the sample melting point (absolute temperature) and 50 ° C. (323 K) or more. Is heated to 4/5 or less, and the surface segregation concentration of the different element contained in the metal or semiconductor in a trace amount is measured. From the time dependence of the surface concentration on the bulk concentration, it is contained in the metal or semiconductor. Method for analyzing trace elements in metals and semiconductors to determine trace element concentrations.
研磨し、更に融点の１／２以上、４／５以下の温度に真
空中で加熱して表面を清浄に仕上げた試料を使用する請
求項１記載の微量元素の分析方法。2. A sample whose surface is mirror-polished, chemically polished to 1 μm or more, and further heated to a temperature of not less than １ ／ of the melting point and not more than 4/5 in vacuum to finish the surface cleanly. Item 7. The method for analyzing trace elements according to Item 1.
である微量元素の原子半径の比が０．９以下または１．
１以上である請求項１記載の微量元素の分析方法。3. The ratio of the atomic radii of a matrix metal and a trace element which is a heterogeneous element to be determined is 0.9 or less.
2. The method for analyzing trace elements according to claim 1, wherein the number is one or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5094583A JP2942688B2 (en) | 1993-04-21 | 1993-04-21 | Method for analyzing trace elements in metals and semiconductors |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5094583A JP2942688B2 (en) | 1993-04-21 | 1993-04-21 | Method for analyzing trace elements in metals and semiconductors |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06308061A JPH06308061A (en) | 1994-11-04 |
| JP2942688B2 true JP2942688B2 (en) | 1999-08-30 |
Family
ID=14114306
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5094583A Expired - Lifetime JP2942688B2 (en) | 1993-04-21 | 1993-04-21 | Method for analyzing trace elements in metals and semiconductors |
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| US7391036B2 (en) | 2002-04-17 | 2008-06-24 | Ebara Corporation | Sample surface inspection apparatus and method |
| JP4499125B2 (en) * | 2007-03-05 | 2010-07-07 | 日本電子株式会社 | Quantitative analysis method in sample analyzer |
| CN111537320A (en) * | 2020-05-15 | 2020-08-14 | 宁波锦越新材料有限公司 | Sample preparation method for GDMS detection and sample |
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