Seil Kim

Analysis and Estimation on EMI Effects in AP-DRAM Interface for a Mobile Platform

Electromagnetic Interference (EMI) is an increasingly important factor in determining whole-system performance of a mobile system. This is driven by size reduction of the mobile platform and the ever-increasing density of electronic components. In this work, we suggest an analysis approach for EMI effects in the interface between an application processor (AP) and dynamic random-access memory (DRAM) by using an I/O driver model including power delivery network (PDN) effects. By applying this approach, the EMI effect by the AP-DRAM interface is able to be accurately estimated when its operating frequency is shifted up/downward depending on the scheme of mobile operations. The EMI effect in the AP-DRAM interface can be characterized by the (1) on-chip metal layout and package layout of the I/O PDN, (2) inserted decoupling capacitance of the I/O PDN, (3) I/O driver properties that define the rising/falling time of signals, and (4) channel properties including crosstalk between adjacent lanes and their frequency response at data transfer. In a time-domain simulation, the extracted I/O driver model was used with extracted AP and memory package models, a channel model, and an interposer. The simulation was carried out by varying input stimulus depending on a bit density ratio, bit length, and a test pattern. As a result, a wide range of spectrum generated by the AP-DRAM interface up to 6 GHz was calculated. The bandwidth of data queue (DQ) signals at the interposer was found to be around 170MHz with multiple harmonics of the fundamental 1.6GHz frequency. In comparison to the measurement, the difference in bandwidth was found to be less than 10MHz and the voltage difference at the harmonics was found to be less than 10dB. Consequently, we proposed an analysis and estimation approach for EMI effects in an AP-DRAM interface which affects the degradation of communication performance in a compact mobile platform and successfully demonstrated its applications for predicting EMI effect in the communication band of interest.

CPI reliability and EMI benefit for MIM CAP embedded C4 package

The necessity of the Metal-Insulator-Metal Capacitor (MIMCAP) devices that helps electrical performance of integrated circuit (IC) has drastically increased for high performance mobile SoC applications. We investigate the magnitude of intrinsic stress employed onto C4 package depends on the MIMCAP size embedded in Silicon die. It is also found that MIMCAP can mitigate 25% stresses imposed on ULK layer in the back-end-of-line (BEOL) process. Moreover, a keen definition of keep out zone (KOZ), the space between MIMCAP as a stress relaxation, is a critical design factor to suppress potential stresses arisen from the MIMCAP embedded C4 package. In this paper, a finite element analysis (FEA) of strain and stress analysis modeling and the benefits to electromagnetic interference for the MIMCAP embedded C4 package will be discussed from design and reliability perspectives and will show superb EMI characteristics with ondie MIMCAP.

42.3: Distinguished Paper: High Resolution AMOLED Panels for Mobile 3D Applications using White OLEDs with Color Filters

An autostereoscopic mobile AMOLED panel has been developed with 6-subpixel structured white OLED devices to maintain image resolution. To achieve the thin-and-light 3D AMOLED panel, fixed parallax barriers instead of liquid-crystal barrier cells are fabricated on the backside of color filter glass. The 5.2-inch AMOLED panel results in ∼5% in crosstalk with ∼1mm panel thickness.