NEPCON West - Fiberoptic Expo Conference Proceedings


BALL STACKED PACKAGE DEVELOPMENT FOR HIGH DENSITY DRAM MODULE APPLICATIONS

Authors: Young Gon Kim, Ph.D. and Ji-Bum Kim
Company: Tessera Technologies Hybnix
Date Published: 12/3/2002   Conference: NEPCON West - Fiberoptic Expo


Abstract: A low-profile, high electrical performance ball-stacked package has been developed for high-density DRAM module applications. The package design is based on a double-column, perimeter ball-out concept that enables low inductance, which has been confirmed by electrical simulation. The optimized design can achieve inductance values of 5 nH or less with die about 7 mm wide. Package-level and system-level thermal performance were simulated with a two-stacked package, SODIMM, and portable PC size motherboard.

No thermal problems were identified during normal operation scenarios. It is recommended, however, to have either a small amount of airflow or a mechanical protector level heat spreader for greater thermal margins. The four-die stacked package passed 1000 cycles of board reliability test at temperatures ranging from -40 to 125°C.

The 1-GB SODIMM product is the outcome of a joint Hynix/Tessera project using a 512Mb DDR SDRAM device. The target application is high-end laptop computers. The 2-die stacked structure is sufficient to achieve this capacity. In order to provide more application flexibility, module thickness is 3.6 mm. This paper covers structure design, ball-out assignment, chip selection and stacking options, electrical and thermal performance, stacking process, and reliability and failure analysis.

Key words: DDR, DRAM, package, FBGA, electrical performance, thermal performance, 3D package, stacked package, DIMM, and SODIMM.



Members download articles for free:

Not a member yet?

What else do you get when you join SMTA? Read about all of the benefits that go along with membership.

Notice: Sharing of articles is restricted to just your immediate work group. Downloaded papers should not be stored on an external network or shared on the internet.


Back


SMTA Headquarters
6600 City West Parkway, Suite 300
Eden Prairie, MN 55344 USA

Phone +1 952.920.7682
Fax +1 952.926.1819