Manufactured and developed in Switzerland, Powatec's UF-300 UV-LED flash exposer is a highly sophisticated device with a high degree of automation. It was developed to meet the highest customer standards. Usually, the UV exposure process is performed after dicing of the wafer to reduce the tape adhesion when picking the die. The device can expose wafers up to 300mm (12") with its corresponding frame with a very high degree of process repeatability. Compared to mercury vapor lamps, the device is immediately ready to operate when switched on. Using only a narrow bandwidth of 365nm in the UVA range, neither harmful ozone nor dangerous mercury gas is generated during LED exposure. The UF-300 is capable of ensuring a homogeneous energy distribution of +/- 5% over the entire irradiation surface using software that controls each individual LED through several driver modules. The dosage recommended by the UV tape data sheet can be selected in single digits of mJ per cm2, and energy quantities of 75 to 1200 mJ/cm2 per exposure cycle are achieved within only 1-3.5 s. For customer-specific needs, it is possible to stretch the limits to dosage levels of over 10'000 mJ/cm2.
The UF-300 always comes with an integrated nitrogen purge which distributes a small quantity of nitrogen evenly over the wafer surface only during UV cycling. This reduces the concentration of oxygen over the area of the UV irradiation. As oxygen has a tendency to inhibit the proper reaction of reducing the tape adhesion under UV irradiation, especially affecting small and fragile die structures during the picking process, the nitrogen purge option is highly recommended.
