Sang Jeen Hong

Microstructure Characterization of TiO 2 Photoelectrodes for dyesensitized Solar Cell using Statistical Design of Experiments

and process variables in the fabrication process of nanocrystalline dye sensitized solar cell. Systematic experiment to identify the effects of process variables on cell’s efficiency has based on broad-band absorption of light by tailor made organometallic dye molecules dispersed on a high surface of TiO

Endpoint Detection in Low Open Area TSV Fabrication Using Optical Emission Spectroscopy

Through-silicon via (TSV) technology is a key enabler for 3-D and 2.5-D integration, which provides low-power and high-bandwidth chip-to-chip communication. During TSV fabrication, over-etching may cause notching at the base of the TSVs, resulting in TSV diameter variations. Endpoint detection (EPD) techniques are critical for controlling TSV diameter, and detecting the endpoint for low open areas presents a serious challenge to process engineers. In this paper, a hybrid partial least squares-support vector machine model for optical emission spectroscopy data are successfully demonstrated for an EPD of low open area TSVs. Accurate EPD results are shown for 120, 80, and 25 \(\mu\) m diameter TSVs.

PECVD Chamber Cleaning End Point Detection (EPD) Using Optical Emission Spectroscopy Data

In-situ optical emission spectroscopy (OES) is employed for PECVD chamber monitoring. OES is used as an addon sensor to monitoring and cleaning end point detection (EPD). On monitoring plasma chemistry using OES, the process gas and by-product gas are simultaneously monitored. Principal component analysis (PCA) enhances the capability of end point detection using OES data. Through chamber cleaning monitoring using OES, cleaning time is reduced by 53%, in general. Therefore, the gas usage of fluorine is also reduced, so satisfying Green Fab challenge in semiconductor manufacturing.

Novel photodefined polymer-clad through-silicon via technology integrated with endpoint detection using optical emission spectroscopy

Silicon interposers with through-silicon vias (TSVs) have been widely explored to obtain high density and high bandwidth communication between chips. To reduce TSV electrical loss and stress, novel photodefined polymer-clad TSVs are fabricated. Moreover, to reduce via under or over etching during TSV fabrication and accurately predict the endpoint for TSV etching, a hybrid partial least squares-support vector machine (PLS-SVM) model of optical emission spectroscopy (OES) data is successfully demonstrated. Accurate endpoint detection results are shown for 80 μm diameter TSVs.

Endpoint detection using optical emission spectroscopy in TSV fabrication

A hybrid partial least squares-support vector machine (PLS-SVM) model of optical emission spectroscopy data is proposed and successfully demonstrated to predict the endpoint detection of through silicon vias (TSVs) etched using the Bosch process. Accurate results are shown for TSVs with diameters of 80 μm and 25 μm.