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Soak of polyurethane-based CMP pads in tungsten slurry and de-ionized water and its effect on retention of thermal and mechanical properties of the pads was studied using Dynamic Mechanical Analysis (DMA), Thermal Mechanical Analysis (TMA), Thermal Gravimetric Analysis (TGA), and Modulated Differential Scanning Calorimetry (MDSC). Simultaneous cross-linking and plastisizing due to soak were established using DMA and MDSC analysis. The stable operating temperature range and its dependence on soak time were determined using TMA analysis. Substantial difference in diffusion behavior of the “soft” and “hard” pads was discovered: diffusion into the hard pads followed Fickian law [1], while diffusion into the multi-layer soft pads was dominated by the fast filling of the highly porous pad surface with liquid.During a traditional CMP process, which involves application of polishing pads and slurry, the pad properties can be substantially and irreversibly changed as the result of slurry/rinse water absorption.The retention of the pad properties after exposure was monitored using such thermal and mechanical techniques, as Thermal Mechanical Analysis (TMA), Dynamical Mechanical Analysis (DMA), Modulated Differential Scanning Calorimetry (MDSC), Thermal Gravimetric Analysis (TGA).

Photomask lifetime has become a challenge since the introduction of high volume manufacturing 193nm photolithograph. Photomask lifetime is being impacted by a broad range of environmental and process factors resulting in inorganics crystals and organic contaminants formation as well as pellicle lifetime issues. Extensive work has been published on strategies for reduction of inorganic crystals photoinduced defects formation mainly focusing on photomask clean process improvements (1-6). This paper will focus on identifying root causes for photoinduced contaminants forming within the pellicle space area as well as identify environmental factors which have the potential of impacting pellicle membrane longevity. Outgasing experiments coupled with 193nm laser exposure tests were conducted to decouple and rank reticle/pellicle storage materials as well as pellicle outgasing contributors to photoinduced defects and identify factors impacting pellicle membrane longevity. Analytical test were conducted to compare the relative levels of reticle storage materials and pellicle outgasing contaminants. Experiments aimed at quantifying the fab environment contribution to photoinduced defects formation and impact on pellicle membrane lifetime will be discussed. Environmental conditions minimizing external contributing factors impacting photomask front side photoinduced defects formation and pellicle membrane longevity will be suggested.

Hot disk metrology represents a transient plane source measurement technique for characterizing thermal conductivity and thermal diffusivity of a wide range of materials. In this technique, the hot disk sensor serves as a heat source and a thermometer. During the measurement, the sensor is sandwiched between two halves of a sample and a constant current is supplied to the sensor. The temperature increase at the sensor surface is strongly dependent on the thermal transport properties of the surrounding material. By monitoring the temperature increase as a function of time, one can determine the thermal conductivity and thermal diffusivity of the surrounding material. The main advantages of the hot disk technique include: wide thermal conductivity range, from 0.005 W/m·K to 500 W/m·K; wide range of materials, from liquid to solid; easy sample preparation; non-destructive; and more importantly, high accuracy (within 2% or better). In this paper, the basic theory of the hot disk technique will be discussed based on first principles. This technique has been successfully used to characterize a variety of thermal interface materials (TIMs) used in electronic packaging. The experimental results are in good agreement with the results obtained by another method.