Feasibility study on rapid thermal processing

The rapid thermal processing is widely used for heating of substrates in microelectronics. The use of radiation (UV/Visible/IR) as source of energy provides several advantages. Apart from thermal effects, photonic effects play a significant role in the RTP. Using array of tungsten halogen lamps as a continuous source of radiation, RTP covers a wide range of processing steps such as annealing, dielectric fabrication, metal alloying, diffusion and chemical vapor deposition. This paper reports an attempt made to use RTP in the field of thick film processing. Firing of thick films is an important high temperature step. The desirable physical and chemical properties of the films can be obtained through firing. A paste consisting of active chemicals, solvent, binder, glass powder is transferred on the substrate by means of screen-printing techniques. Further heating the substrates to about 600 °C fires this patterned thick film. This paper reports a novel technique for firing the paste in RTP system. The parameters viz. temperature and time were optimized for resistive paste of Cd–Cu–Cl. The thick films thus obtained were studied for their photosensitivity, I–V characteristics and microscopic structures.