Preencapsulation cleaning methods and control for microelectronics packaging

A modern electronic device is a complex three-dimensional structure that consists of millions of components on each single IC chip. Such a device requires effective cleaning to ensure its long-term reliability. In order to achieve reliability without hermeticity with these IC devices, various organic (silicones, epoxies, polyimides, etc.) and inorganic (silicon oxides, silicon nitrides, etc.) coating materials are used for protection. However, packaging contaminated IC devices guarantees device failure, and preencapsulation cleaning methods and controls are the most critical process steps in determining the reliability of the packaged IC devices. We have prepared well-controlled substrates (such as SiO₂, SiN, SiON) for our cleaning experiments and have developed a series of cleaning processes that achieve the best cleaning results prior to encapsulation. These cleaning processes consist of both chlorofluoro hydrocarbon (CFC) and non-CFC solutions including (d-limonene), isopropanol, new surfactants, high purity, deionized water (DI H₂O), peroxide (H₂O ₂), etc. Furthermore, we have demonstrated that contact angle measurements in a 100% RH environment are simple, fast, and reliable in detecting the substrate surface cleanliness, particularly with respect to hydrocarbon contamination on the first ~10 angstroms of surface layers. ESCA and contact angle measurement analyses are also used to quantify and correlate the cleaning processes. Results of these processes are given in this report