Single wafer processing in semiconductor manufacturing was first introduced almost 15 years ago. Dry etching equipment initially adopted the technology for various processing advantages including lowering the cost of consumables and high repeatability and reliability of the process.
In some instances, wet etch has been slower to adapt single wafer processing because throughput is impacted. But several key processes in wet etching are now trending toward single wafer. The Nitride Etch process is a prime example for the following reasons:
Operating at elevated temperatures, like in the silicon nitride etch bath, is complicated by the requirement that the acid concentration must be strictly maintained to regulate the temperature of the bath. In-line heaters are one way to maintain the needed temperature of the etch process and ensure repeatability. Different types of in-line heaters for different applications. Different types of in-line heaters designed for different materials. For high purity fluids heating and gas heating inline heaters, quartz is the ideal material. But for heating HF ( hydrofluoric acid ), KOH ( potassium hydroxide ), and other high PH chemistries quartz has limitations, IMTEC found a better solution by using high purity PFA as a heat transfer material. Accuheat in-line heaters are specifically designed for the silicon nitride etch application. The traditional application uses the in-line heater as part of the recirculation loop, either as the sole heat source or in combination with a heated quartz tank for faster heat-up times and better control.Accuheat In-line Heaters - Key Benefits