A novel bumping material, which is composed of a resin and Sn3Ag0.5Cu (SAC305) solder power, has been developed for the maskless solder-on-pad technology of the fine-pitch flip-chip bonding. The functions of the resin are carrying solder powder and deoxidizing the oxide layer on the solder power for the bumping on the pad on the substrate. At the same time, it was designed to have minimal chemical reactions within the resin so that the cleaning process after the bumping on the pad can be achieved. With this material, the solder bump array was successfully formed with pitch of 150 µm in one direction.

Existing technologies in disaster and safety communication networks (DSCNs) face problems such as narrow bandwidth, low transmission rate, and difficulty in securing channels. Conversely, public safety long-term evolution (PS-LTE) technology provides high-speed, low-latency, quick-setup, and high-security data access for multimedia-based mission-critical services. To perform tests on each unit of core equipment with PS-LTE technology, a new call model such as push-to-talk, which is a service representing PS-LTE, is required. Moreover, objective and consistent metrics and methods are required for administering tests on the unique functions of DSCNs newly constructed with PS-LTE technology. This paper proposes a call model for the core facilities of DSCNs established in Korea, and it also suggests test and verification methods for all the areas of PS-LTE, including mission-critical push-to-talk, evolved multimedia broadcast and multicast service, and coverage and quality assessment for wireless services.