Separation Characteristics of an LMPA-Polymer Mixture for the Encapsulation of Organic Light-Emitting Diode

An encapsulation method using the separation of low melting point alloy (LMPA) and a polymer from an LMPA-polymer mixture is proposed. Sn-Bi alloy and epoxy were used for the mixture. Separation was conducted using a two-step heat treatment of 160 °C for 5 min and 180 °C for 5 min. We found that the flux contained in the Sn-Bi solder played an important role in the separation process. A Cu sacrificial layer was introduced using the sputtering method under the Sn-Bi layer with thickness variations of 1500, 3000, and 6000 Å. Using the 6000-Å-thick Cu layer, the LMPA formed a well-separated and continuous sealing line. This double-line structure shows good potential for use as a sealing line for organic light-emitting diode encapsulation.