Soon Hyeong Kwon

Measurement of adhesion and bonding strength studies in 3D interconnect structures using atomic force microscopy

The wafer bonding process has become a flexible approach to material and device integration. The bonding strength in 3-dimensional processes is a crucial factor in various interface bonding processes such as silicon to silicon, silicon to metal, and oxide to adhesive intermediates. A method for measurement of bonding strength is proposed utilizing an ‘atomic force microscopy (AFM) applied carbon nanotube (CNT) probe tip’ which requires relatively simple preparation of sample and is able to measure bond strength regardless of film type. The bonding strength of the SiO2-Si surfaces cleaned with SPFM was 0.089 J/m2, while the bonding strength of surfaces cleaned with RCA 1 (NH4OH:H2O:H2O2) was 0.044 J/m2. This work verified the possibility that the new method is capable of accurately measuring bonding strength. It was also confirmed that more effective bonding is possible after cleaning with SPFM.

Effect of chemical mechanical treatment on the optoelectronic properties in CMOS image sensor

This paper presents the effect focal length variation by controlling chemical mechanical polishing (CMP) processes on the CIS optical performance. White sensitivity was drastically increased, and saturation signal variation and dead zone deviation were reduced. These experimental results showed that controlled focal length was able to increase CIS optoelectronic performance.

Radiofrequency characteristics of ionized sputtered tantalum nitride thin-film resistor in CMOS device

We report the analysis of the radiofrequency (RF) characteristics according to the size, area, and shape of TaN thin-film resistor (TFR) layers. As the TFR size increased, its characteristics were degraded with increasing frequency owing to the increased capacitive parasitic components. As the frequency increased from 1 MHz to 10 GHz, the effective resistance decreased by approximately 12.5%, 16.4%, and 37.8% when the resistor widths and lengths were 0.5 × 20, 1 × 40, and 2 × 80 μm, respectively. To optimize the performance of the high-frequency TFR, ensuring RF isolation via sufficient separation from the silicon substrates was crucial. To realize this RF isolation, methods for minimizing the effect of lossy Si substrates by using TFRs with a smaller area or by forming a patterned ground shield should be introduced.

Application of monitoring methodology in carbon complex contained solution using surface-enhanced Raman spectroscopy (SERS)

ABSTRACT Raman spectroscopy is employed to obtain information that cannot be obtained using other technologies, using inelastic scattering. The development of laser technology enables Raman spectroscopy to overcome its limits and succeed in various fields. For example, compared with other analysis methods that use light, it does not require a sample preparation or long measuring time—thus, it is a great breakthrough for in situ process applications. Also, it is difficult to analyze functional groups that are combined and the influence on the reaction is analyzed during the reaction in chemical solutions. Therefore, Raman spectroscopy provides an analytic method and assists in every step to increase the accuracy of the chemical process. Lately, developed surface-enhanced Raman spectroscopy (SERS) are used in precise analyzing methods. High-resolution SERS needs a specific substrate to satisfy each purpose. Raman spectroscopy is now advanced to be more a powerful analytic tool, combined with surface-enhancing technology, atomic force microscopy (AFM), and other technology.

Chemical Analysis of Patterned Mask Cleaning in Organic Light Emitting Diode Fabrication with Raman Spectroscopy

Abstract Despite the continually improving efficiency of the fabrication process used to manufacture the organic light emitting diode (OLED) emitter layer, which uses a shadow mask, a method for the cleaning and recycling of the shadow mask is still lacking. One of the main reasons for this is the absence of a quantitative/qualitative method to analyze the cleaning solution using simple in situ measurements. Recently, Raman analysis has become popular because of its convenience, ease of use, and suitability for in situ measurements. Thus, Raman spectroscopy has the capacity to analyze the solution used for cleaning shadow masks. A particular advantage of this approach is that it can detect organic contaminants in the cleaning solution, which are caused by the residue that remains on the shadow mask after the OLED emitter layer fabrication process. Raman spectroscopy has an advantage for analyzing solution condition and contaminant detection between the cleaning solution and organic chemical by using the Raman peak and fluorescence integration method.