鉛フリー無電解Niめっき皮膜中の共析物がはんだ実装信頼性に及ぼす影響

Title: 鉛フリー無電解 Ni めっき皮膜中の共析物がはんだ実装信頼性に及ぼす影響 Authors: 土田徹勇起, 大久保利一, 狩野貴宏, 荘司郁夫 Issue Date:2013 年 1 月 20 日 Publisher: 一般社団法人エレクトロニクス実装学会 Citation: エレクトロニクス実装学会誌 Vol.16 No.6(2013)484-491 次ページより本文を掲載致します

論文1. 緒言 研究論文 16 6 18 (2013) 鉛フリー無電解 Ni めっき皮膜中の共析物がはんだ実装信頼性に及ぼす影響 土田徹勇起 *, 大久保利一 *, 狩野貴宏 **, 荘司郁夫 *** The Influence of Incorporated Additives in Lead-Free Electroless Nickel Plating Film on the Reliability of Solder Joint Tetsuyuki TSUCHIDA*, Toshikazu OKUBO*, Takahiro KANO**, and Ikuo SHOHJI*** * 345-8508 4-2-3 ** 376-8515 1-5-1 *** 376-8515 1-5-1 * Technical Research Institute, TOPPAN PRINTING CO., LTD. (4-2-3 Takanodaiminami, Sugito-machi, Kitakatsushika-gun, Saitama 345-8508) ** Graduate School of Engineering, Gunma University (1-5-1 Tenjin-cho, Kiryu-shi, Gunma 376-8515) *** Division of Mechanical Science and Technology, Faculty of Science and Technology, Gunma University (1-5-1 Tenjin-cho, Kiryu-shi, Gunma 376-8515) 概要 Ni/Au Ni/Pd/Au Ni Ni Ni Ni/Au Ni/Pd/Au Ni IMC Ni Abstract Electroless Ni/Au or electroless Ni/Pd/Au plating is widely used as surface finishing for electronics assembly. Conventional electroless Ni plating films contain small amounts of lead derived from additives in their plating baths. However, it is expected that lead-free electroless nickel plating will be required if stricter environmental regulations are in force. In this study, the reliability of solder joints with lead-free electroless Ni/Au and Ni/Pd/Au plating was investigated. It was found that certain factors, such as Ni corrosion pitting and the behavior of the IMC (thickness, ratio of components and shape), affect the reliability of the lead-free solder joint in complex ways. Moreover, it was confirmed that these factors vary with the amount of additives (bismuth and sulfur) incorporated into these lead-free plating films. Key Words: Lead-free Electroless Ni/Pd/Au, Lead-free Solder Joint, Nickel Plating Additives Ni/Au Ni/Pd/ CSP (Chip Size Package) BGA (Ball Grid Array) Cu 1) RoHS (Restriction of Hazardous Substances) ELV (End-of Life Vehicles Directive) 2) Sn-3wt%Ag- 0.5wt%Cu (SAC) Ni/ Au SAC SAC Ni/Pd/Au 3),4) Au Ni 1/10 ppm ppm ppm Ni Ni 5),6) Ni RoHS ELV 1,000 ppm JIG (Joint Industry Guideline) 7) Ni Ni Vol. 16 No. 6 (2013) 1

論文2 Vol. 16 No. 6 (2013) Ni Ni/Pd/Au 5)7) Ni Ni Ni/Au Ni/Pd/Au Ni 9) 3 μm Ni Ni Ni 2. 実験方法 2.2 無電解 Ni/Pd/Au めっき皮膜と供試材の作製 2.1 無電解 Ni めっき皮膜の作製 Ni AF Table 1 Ni Ni A Ni BE Ni F Ni Table 1 Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) 8) φ300 μm Ni X 3 μm Ni 2 mg Ni SUS Ni g 8) Ni g Ni mg φ300 μm Cu Pd Cu Table 1 Ni 3 μm Pd 4 wt% 0.1 μm Au 0.05 μm Ni/Au Ni/Pd/Au Ni Cu Ni φ300 μm Ni/Au Ni/Pd/Au φ350 μm SAC 100 ppm 130 C 238 C220 C 30 1 1 4 5 1 120 C 3 FC (Flip Chip)-BGA (intermetallic compounds; IMC) Table 1. Analysis of additive concentrations in electroless Ni plating films Ni plating Types of additives Concentration of additives in the Ni plating film bath in the Ni plating bath phosphorus (wt%) bismuth (ppm) sulfur (ppm) lead (ppm) A sulfer compounds 7.41 201 B bismuth, sulfer compounds 6.99 140 96 C bismuth, sulfer compounds 5.95 130 264 D bismuth, sulfer compounds 8.33 170 132 E bismuth, sulfer compounds 5.80 340 1,000 F lead, sulfer compounds 6.45 142 270

論文 120 C IMC 2.3 めっき皮膜の評価 2.2 Ni/Au Ni/Pd/ Au Au Au scanning electron microscope (SEM) Ni Pd Au Ni/Pd/Au Focused Ion Beam (FIB) SEM Pd Ni 2.4 はんだ実装信頼性評価方法 2.2 Dage 4000HS 50 μm 1 m/sec Electron Probe X-ray Microanalyzer (EPMA) 70% 3070% +IMC 30% IMC Fig. 1 IMC Fig. 1 Examples of fracture mode observed after ball shear test IMC IMC 3. 実験結果と考察 3.1 無電解 Ni めっき皮膜中の共析物 Table 1 BD Ni ppm F E Ni 1,000 ppm Ni 5.808.33 wt% 2) Ni 10) Ni 3.2 めっき皮膜の耐食性評価 3.2.1 Ni/Au Ni Ni/Au Au Ni Fig. 2(a) Au B C Ni C E Ni D Ni Ni Ni Fig. 2 SEM images of the electroless Ni and Pd plating surface after stripping immersion Au films Vol. 16 No. 6 (2013) 3

論文4 Vol. 16 No. 6 (2013) 3) Ni E Ni Ni D Ni Ni 3.2.2 Ni/Pd/Au Pd Ni/Pd/Au Au Pd Fig. 2(b) Fig. 2(a) Fig. 2(b) Ni Pd Au Au Pd Pd Ni (Ni>Pd>Au) Ni Pd Ni Pd Au Ni Ni Ni/Pd/Au FIB SEM 3.2.3 Ni/Pd/Au Fig. 3(a), (b) AE Ni/ Pd/Au Fig. 3(a) A Pd Ni Fig. 3(b) E Ni Pd Ni/Pd/Au Ni Pd Ni 4) Ni/Pd/Au Ni Ni Fig. 3 Fig. 3 SEM images of the electroless Ni/Pd/Au plating films cross-sectioned by FIB (a) bath A, (b) bath E Ni Au Ni Au Au Ni Au Ni Ni Ni 10 wt% Ni Pd Ni/Pd Au Ni Ni/Pd/Au 5) 3.3 はんだ実装信頼性評価 (1 回リフロー ) 1 Ni/Au Ni/Pd/Au Fig. 4 Ni/Au Ni E 60% F Ni/Pd/Au A 100% Ni/Au Ni/Pd/Au Ni/Au Ni/ Au Ni/Pd/Au Ni

論文Au Pd Ni/Au Fig. 4 The reliability of solder joint on various electroless Ni/Au and Ni/Pd/Au plating films after single reflow soldering Ni 11) Ni BE F A Ni/Au 30% A Ni/Pd/Au Fig. 3 NiPd Ni/Pd/Au Ni Au Pd Ni A F Ni 10 wt% Ni 5)7) Fig. 4 1 Ni/Pd/Au Ni 3.4 はんだ実装信頼性評価 (5 回リフロー ) Ni/Pd/Au 5 Fig. 5 1 Ni BE5 BCD Fig. 5 The reliability of solder joint on various electroless Ni/Pd/Au plating films after 5 times reflow soldering 70%60%60% A 30% E 100% Ni 1 Ni AF IMC Fig. 6 Ni/Pd/Au 1 5 SAC IMC Fig. 7 5 CE Fig. 6 1 5 IMC 5 5 A IMC 12 μm BF IMC IMC Vol. 16 No. 6 (2013) 5

論文6 Vol. 16 No. 6 (2013) 12) Ni IMC 12) A IMC BF IMC 6 μm Table 2 EPMA IMC Sn, Ni, Cu IMC (Cu, Ni) 6 Sn 5 Fig. 7 CE IMC E IMC C IMC IMC E E Ni Table 2 IMC E Fig. 6 Fig. 7 Thickness of IMC layers formed in solder ball joints with electroless Ni/Pd/Au plating films after single and 5 times reflow soldering Back-scattered electron images of cross sections of solder ball joints with eletroless Ni/Pd/Au plating films after 5 times reflow soldering (a) bath C, (b) bath E IMC Ni A Ni Fig. 3 Ni Au IMC Sn/Ni/Cu IMC Ni 3.5 はんだ実装信頼性評価 ( 時効処理 ) Ni/Pd/Au Fig. 8 Fig. 8 E 70% Fig. 9 AF SEM E IMC IMC A, B, C IMC D, F 5 Ni Fig. 8 Table 2. EPMA quantitative analysis results of IMC in solder ball joints with electroless Ni/Pd/Au plating films after 5 times reflow soldering Ni plating bath element (at%) Sn Ni Cu A 49.7 10.0 40.3 B 42.7 21.8 35.5 C 41.4 20.4 38.2 D 38.6 33.7 27.7 E 49.2 11.5 39.3 F 33.7 40.5 25.8 The reliability of solder joint on various electroless Ni/Pd/Au plating films after aging at 120 C for 3 weeks

論文IMC 1 Fig. 10(a), (b) C Ni/Pd/ Au 1 Fig. 9 Fig. 10 SEM images of cross sections of solder ball joints with eletroless Ni/Pd/Au plating films after aging 120 C for 3 weeks (a) bath A, (b) bath B, (c) bath C, (d) bath D, (e) bath E, and (f) bath F EPMA mapping analysis results of solder bal joint with electroless Ni/Pd/Au plating films after (a) single reflow soldering and (b) aging at 120 C for 3 week (bath C) Fig. 10(a), (b) (b) Ag 3 Sn Ag 3 Sn 13) Ni 5. 結論 Ni Ni/Au Ni/Pd/Au (1) Ni ppm (2) Ni Ni/Pd/Au Ni (3) Ni Ni/Pd/Au Ni Pd (4) Ni Ni/Pd/Au Ni (5) Ni (6) Ni Ni Ni Pd IMC 謝辞 FIB BT 2013.2.21- Vol. 16 No. 6 (2013) 7

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