DEVELOPMENT OF COOLING TECHNOLOGY IN A MEGASONIC CLEANING SYSTEM FOR FLAT PANEL DISPLAY
The manufacturing processes of Flat panel displays (FPDs) such as liquid crystal displays (LCDs), plasma display panels (PDPs) and light-emitting diodes (LEDs), are similar to semiconductor fabrication processes. Among them, the cleaning process is considered to be a crucial step in preparing a clean surface for the next step. Until now, cleaning processes of FPDs have been usually wet processes that use chemicals. With continual decrease of feature size, the particle sizes that need to be removed have become smaller, and as such, cleaning requirements have become much severer than ever before. To solve these problems, ultrasonic cleaning systems were introduced in manufacturing semiconductors and FPDs. Megasonic system are actuated with a lead zirconate titanate (Pb(Zr·Ti)O3 (PZT)) actuator, which is attached to a quartz waveguide. It dissipates much heat, so cooling should be done in the system.
In this work, cooling technology in a megasonic cleaning system for removal of micro/nano particles from FPD surfaces with lower power consumption and less use of chemicals and UPW was developed. The structures and methods for cooling the system are explained. And cooling experiments were performed with different solutions.
As a result, to maintain the temperatures of a PZT actuator and a waveguide under 70°C, air with water cooling solution was decided for the system with input power of 100 W.