Page 32 - Chip Scale Review Sep Oct_2022-digital

grinding wheel type A would be the best
choice. Finally, the double-sided SiP
structure passed reliability requirements
including pre-condition MSL 3, TCT (1,000
cycles), u-HAST (96 hours) and HTSL
(1,000 hours). The double-sided SiP can
provide an innovative solution to address
the small form factor, cost reduction,
electrical performance, and time-to-market
requirements for 5G and wearable products
in the near future.
Table 3: Summary of reliability tests conducted.
References
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We used the 3-point test to check the reliability test results had passed as shown SiP module,” Proc. 67th Electronic
package (PKG) die strength. The greater in Table 3. Comp. and Tech. Conf. (ECTC), 2017,
PKG strength was achieved using a fine pp. 1039-1044.
grit size with wheel D because of the higher Summary 2. M. Tsai, R. Chiu, D. Huang, F. Kao,
die strength that can be accomplished with Compared to a single-sided SiP structure, E. He, J. Y. Chen, et al., “Innovative
the smooth silicon die surface and mold a double-sided SiP structure can provide packaging solutions of 3D double side
surface. The test results of the roughness good thermal performance by using a molding with system in package for
and 3-point bending using the different thermal pad design and TIM (i.e., Ag epoxy IoT and 5G application,” Proc. 69th
grinding wheel types are shown in Figures with 25W/mK with 0.99x θJA ratio with ECTC, 2019, pp. 700-706.
6a and 6b. 24% thermal enhancement, and 0.75y θJB 3. M. Tsai, R. Chiu, Ming-fan Tsai,
with a 38% thermal enhancement). The E. He, E. Yang, T. Chang, et al.,
Reliability results normal EMC with TIM achieved a better “Heterogeneous integration of double
The grinding wheel selection can warpage result because of the low CTE side SiP for IoT and 5G application,”
enhance the package strength and reduce mismatch during the molding process done Proc. 71st ECTC, 2021, pp. 1038-1043.
the risk of die and package cracking caused on the structure. 4. T-W. Liao, W-H. Lai, H-C. Shih,
by structural warpage. The finer grinding The double-sided SiP package provides D-L. Chen, D. Tarng, CP Hung,
wheel type (wheel type D) resulted in a the small form factor and good electrical “Mechanical reliability analysis of
greater package die strength due to the performance required for 5G and wearable dual side molding SiP module,” Proc.
smooth silicon die and mold surface— electronics applications. For the advanced 2021 Inter. Conf. on Electronics
but in contrast, it increased process time. double-sided SiP structure, we studied Packaging (ICEP), 2021, pp. 93-94.
The double-sided cross-section image of the effects of different die thicknesses and 5. B-H. Ma, D. Ho, Y-P. Wang, F. Yen,
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(u-HAST) at 130ºC for 96 hours, and high- surface, but it resulted in a lower grinding 72nd ECTC, 2022, pp. 18-23.
temperature storage life (HTSL) testing at throughput. To achieve a higher throughput,

Biographies
David Wang is a Department Manager, Corporate R&D at Siliconware Precision Industries Co., Ltd.,
Taichung, Taiwan, R.O.C. He has over 25 years of industry experience especially focusing on fan-out packaging
technology development and advanced assembly analysis. He has published over 10 conference papers and
patents. Email: davidwang1@spil.com.tw

Mike Tsai is a Technical Deputy Manager, Advanced SiP Product Integration at Siliconware Precision
Industries Co., Ltd., Taichung, Taiwan, R.O.C. He received his MS degree from National Chung Hsing U.
(NCHU). He has over 10 years of job experience and published 11 papers in the semiconductor industry, with a special focus on
FC, PoP and SiP of advanced assembly technology.

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