Tae-soo Kim

P-136: A Study on the Dynamic Characteristics of Bend Cell for Practical Application of OCB mode LCD

We have investigated on the dynamic LC characteristics of bend cells to achieve a high performance optical property and operational reliability in bend state of OCB (optically compensated bend) mode for practical application. Based on the different phase-transformation features between initial bend transition and bend to splay relaxation, the dynamic LC response of OCB mode could be practically controlled up to a certain degree using specific dynamic driving scheme with consideration of dynamic response characteristics. Consequently, the evaluated optimum driving scheme was applied to proto-type of 2.03″ LTPS QVGA-OCB LCD and the obtaining results were evaluated within the framework of practical application for mobile display without deliberation of motion blur.

48nm Pitch cu dual-damascene interconnects using self aligned double patterning scheme

For sub-64nm pitch interconnects build, it is beneficial to use Self Aligned Double Patterning (SADP) scheme for line level patterning. Usually a 2X pitch pattern was printed first, followed by a Sidewall Image Transfer (SIT) technique to create the 1X pitch pattern. A block lithography process is then used to trim this pattern to form the actual designed pattern. In this paper, 48nm and 45nm pitch SADP build will be used as examples to demonstrate the SADP patterning scheme. General discussions about this patterning scheme will be provided including: 1) the process flow of this technique, 2) benefits of the technique vs. pitch split approach, 3) the design impact and limitation, and 4) the extendability to smaller line pitch build.

P-135: Fast Bend Transition of the Pi-Cell at Low Temperature

We have developed fast bend transition method of pi-cell in low temperature. This cell requires a transition of the liquid crystals (LC) from an initial splay state to bend transition before normal driving operation. This study analyzed the conditions under which this transition is generated in low temperature. Consequently, a method of fast bend transition by applying waveform that make the most of LCs dynamic response, using structure of top-gate electrode and surface alignment in Low Temperature Poly-Silicon (LTPS) Thin Film Transistor (TFT) cell was established.

Successful recovery of moisture-induced TDDB degradation for Cu/ULK(k=2.5) BEOL interconnect

Cu/ULK(k=2.5) dual Damascene back end of line(BEOL) dielectric degradation was studied with respect to post Cu CMP delay prior to dielectric diffusion barrier deposition. The threshold of the delay time was observed beyond which line-to-line leakage current increased rapidly while the dielectric breakdown voltage decreased. This air exposure-dependent degradation was attributed to moisture absorption by damaged ULK during integration, and caused premature TDDB (time-dependent dielectric breakdown) failure. It was found that combination of moisture removal by damage-free UV and mild plasma treatment was able to restore dielectric breakdown voltage as well as TDDB time to failure even well past the threshold of delay time.

Ramp Load/Unload Velocity Control of VCM Using BEMF in HDD

Since most of small form-factor drives have a load/unload mechanism and the flying height of the head is getting lower as the capacity of disk drives increases, the load/unload velocity becomes one of the important factors to ensure the reliability of the load/unload mechanism. To control the load/unload velocity accurately, velocity sensing is essential. In this paper, we introduce a very practical method that acquires the load/unload velocity from the back electromotive force (BEMF) of a voice coil motor (VCM) and propose a calibration method for measuring the BEMF from a given circuit. Moreover, the effect of calibration error and temperature variation on the measurement of BEMF is shown by simulation. Then, this present method is applied to the load/unload velocity controller and is verified from the experimental result.