Browsing by Author "Kuo, Jui-Chao"

Now showing 1 - 5 of 5

Extremely anisotropic single-crystal growth in nanotwinned copper
(2014-10-01)
Lu, Chia-Ling
;
Lin, Han-Wen
;
Liu, Chien-Min
;
Huang, Yi-Sa
;
Lu, Tien-Lin
By electroplating of nearly unidirectionally < 111 >-oriented nanotwinned and fine-grained Cu on a Si wafer surface followed by annealing at 400-500 degrees C for up to 1 h, we grew many extremely large < 100 >-oriented single crystals of Cu with sizes ranging from 200 to 400 mu m. By patterning and annealing the nanotwinned Cu films, we grew an array of < 100 >-oriented single crystals of Cu with sizes ranging from 25 to 100 mu m on Si. In comparison, single-crystal nano-wire growth is a one-dimensional anisotropic growth process, in which the growth along the axial direction is much faster than in the radial direction. We report here a bulk-type two-dimensional crystal growth of an array of numerous < 100 >-oriented single crystals of Cu on Si. This growth process has the potential for microbump applications in three-dimensional integrated circuit-packaging technology for hand-held consumer electronic products.
Fabrication of arrays of (100) Cu under-bump-metallization for 3D IC packaging
(2015)
Chiu, Wei-Lan
;
Lu, Chia-Ling
;
Lin, Han-Wen
;
Liu, Chien-Min
;
Huang, Yi-Sa
Due to the thousands of microbumps on a chip for 3D ICs, the precise control of the microstructure of all the material is required. The nearly < 111 >-oriented nanotwinned and fine-grained Cu was electroplated on a Si wafer surface and annealed at 400-500 C for 1 h, many extremely large < 100 > oriented Cu crystals with grain sizes ranging from 200 to 400 um were obtained. The < 111 >-oriented Cu grains were transformed into super-large < 100 >-oriented grains after the annealing. In addition, we patterned the < 111 >-oriented Cu films into pad arrays of 25 to 100 um in diameter and annealed the nanotwinned Cu pads with same conditions. An array of < 100 >-oriented single crystals Cu pads can be obtained. Otherwise, single-crystal nano wire growth displays a process by one-dimensional anisotropic growth, in which the growth along the axial direction is much faster than in the radial direction. This study reported here a bulk-type two-dimensional crystal growth of an array of numerous < 100 >-oriented single crystals of Cu on Si. The growth process in 3D IC has the potential for microbump applications packaging technology.
Microstructure control of unidirectional growth of eta-Cu6Sn5 in microbumps on < 1 1 1 > oriented and nanotwinned Cu
(2013-08-01)
Lin, Han-wen
;
Lu, Chia-ling
;
Liu, Chien-min
;
Chen, Chih
;
Chen, Delphic
Anisotropic microstructure is becoming a critical issue in microbumps used in 3-D integrated circuit packaging. We report here an experimental approach for controlling the microstructure of eta-Cu6Sn5 intermetallic compound in microbumps by using < 1 1 1 > oriented and nanotwinned Cu pads as the under-bump-metallization. By electroplating arrays of large numbers of < 1 1 1 > oriented and nanotwinned Cu pads and by electroplating the Sn2.3Ag solder on the pads, we form eta-Cu6Sn5 in the reflow at 260 degrees C for 1 min. The eta-Cu6Sn5 showed a highly preferential growth along the < 0 0 0 1 > direction. As reflow time is extended, the preferred texture of eta-Cu6Sn5 changed to {2 (1) over bar (1) over bar 3}. The results indicate that we can control the uniform microstructure of eta-Cu6Sn5 intermetallic by controlling the microstructure of the Cu under-bump-metallization. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Novel EBSD preparation method for Cu/Sn microbumps using a focused ion beam
(2012-12-01)
Liu, Tao-Chi
;
Chen, Chih
;
Chiu, Kuo-Jung
;
Lin, Han-Wen
;
Kuo, Jui-Chao
We proposed a novel technique developed from focused ion beam (FIB) polishing for sample preparation of electron backscatter diffraction (EBSD) measurement. A low-angle incident gallium ion beam with a high acceleration voltage of 30 kV was used to eliminate the surface roughness of cross-sectioned microbumps resulting from mechanical polishing. This work demonstrates the application of the FIB polishing technique to solders for a high-quality sample preparation for EBSD measurement after mechanical polishing. (C) 2012 Elsevier Inc. All rights reserved.
The preferential growth of eta-Cu6Sn5 on (111) uni-directional Cu pads
(2012)
Lin, Han-wen
;
Lu, Jia-ling
;
Liu, Chen-min
;
Chen, Chih
;
Tu, King-ning