An electrochemical investigation of additive effect in trench-filling of ULSI interconnects by electroless copper deposition

被引:19
作者
Hasegawa, Madoka
Yamachika, Noriyuki
Okinaka, Yutaka
Shacham-Diamand, Yosi
Osaka, Tetsuya
机构
[1] Waseda Univ, Sch Sci & Engn, Dept Appl Chem, Shinjuku Ku, Tokyo 1698555, Japan
[2] Waseda Univ, Adv Res Inst Sci & Engn, Shinjuku Ku, Tokyo 1698555, Japan
[3] Tel Aviv Univ, Iby & Aladar Fleischman Fac Engn, Dept Elect Engn Phys Elect, IL-69978 Tel Aviv, Israel
关键词
electroless deposition; copper; additive; ULSI interconnects;
D O I
10.5796/electrochemistry.75.349
中图分类号
O646 [电化学、电解、磁化学];
学科分类号
081704 ;
摘要
The filling of trenches in ULSI interconnect structure by electroless copper deposition was investigated for the effect of bath additives. The additive effect was found to depend strongly on the reducing agent used in the bath. Void-free trench-filling was achieved by using polyethylene glycol (PEG) as an inhibiting additive in the bath containing glyoxylic acid as the reducing agent, while the combined addition of 8-hydroxy-7-iodo-5-quinoline sulfonic acid (HIQSA) and PEG was necessary for achieving void-free filling in the bath containing formaldehyde as the reducing agent. The effect of PEG on trench filling in the former bath was studied in detail based on electrochemical measurements. It is suggested that the rinse water remaining in trenches before electroless deposition causes a decrease in PEG concentration at the trench bottom during copper filling. The addition of PEG was found to shift the deposition potential in the negative direction. A new potential measuring apparatus was devised and used in model experiments, which revealed that the deposition potential depends on the local concentration of PEG at the trench bottom, where it is expected to be low. The observed preferential growth of copper deposit at the trench bottom is thus attributed to the effects of the variation of PEG concentration within the trenches on the deposition rate and potential.
引用
收藏
页码:349 / 358
页数:10
相关论文
共 26 条
[1]   Damascene copper electroplating for chip interconnections [J].
Andricacos, PC ;
Uzoh, C ;
Dukovic, JO ;
Horkans, J ;
Deligianni, H .
IBM JOURNAL OF RESEARCH AND DEVELOPMENT, 1998, 42 (05) :567-574
[2]   ELECTROLESS COPPER - AN ALTERNATIVE TO FORMALDEHYDE [J].
DARKEN, J .
TRANSACTIONS OF THE INSTITUTE OF METAL FINISHING, 1991, 69 :66-69
[3]   THE MECHANISM OF ELECTROLESS CU DEPOSITION - EXTRACTION OF THE OXIDATIVE AND REDUCTIVE ELECTROCHEMICAL HALF-CELL CURRENTS FROM A COMPLETE BATH [J].
FELDMAN, BJ ;
MELROY, OR .
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 1989, 136 (03) :640-643
[4]   Effects of additives on copper electrodeposition in submicrometer trenches [J].
Hasegawa, M ;
Negishi, Y ;
Nakanishi, T ;
Osaka, T .
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 2005, 152 (04) :C221-C228
[5]  
HASEGAWA M, UNPUB APPL PHYS LETT
[6]   Void-free trench-filling by electroless copper deposition using the combination of accelerating and inhibiting additives [J].
Hasegawa, Madoka ;
Okinaka, Yutaka ;
Shacham-Diamand, Yosi ;
Osaka, Tetsuya .
ELECTROCHEMICAL AND SOLID STATE LETTERS, 2006, 9 (08) :C138-C140
[7]   ELECTROLESS COPPER DEPOSITION PROCESS USING GLYOXYLIC-ACID AS A REDUCING AGENT [J].
HONMA, H ;
KOBAYASHI, T .
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 1994, 141 (03) :730-733
[9]   Leveling of 200 nm features by organic additives [J].
Kelly, JJ ;
West, AC .
ELECTROCHEMICAL AND SOLID STATE LETTERS, 1999, 2 (11) :561-563
[10]   Improvement of electrolessly gap-filled Cu using 2,2′-dipyridyl and bis-(3-sulfopropyl)-disulfide (SPS) [J].
Lee, CH ;
Lee, SC ;
Kim, JJ .
ELECTROCHEMICAL AND SOLID STATE LETTERS, 2005, 8 (08) :C110-C113