PURPOSE: To remove phosphor substance completely from shadow mask structure by cleaning the shadow mask structure through hot-water cleaning mainly composed of wet supersonic cleaning prior to sealing process.

CONSTITUTION: After forming phosphor face on the inner face of panel, the shadow mask structure is cleaned through hot-water cleaning mainly composed of wet supersonic wave cleaning prior to sealing process. When cleaning a shadow mask structure adhered with phosphor substance containing photo-sensitive binder through cleaning method mainly composed of wet supersonic wave method, the removal rate of phosphor substance will be 60% for hot water of 40°C after applying supersonic wave for 2min and spraying hot water of 30°C for 15min while it may reach to 100% for hot water of 100°C after applying supersonic wave longer than 1min and spraying hot water of 40°C for 15sec.