Articles you may be interested inStudy of machine to machine overlay error for sub-60 -nm memory devices

Dissolved resist effect on the global CD has been studied in detail in an effort to understand the CD reduction phenomenon due to develop loading. Spin spray process also showed the loading effect although it is less than that of puddle process. In rotating system like spin spray develop process, it is necessary to understand the fluids effect of developed resist to improve the local and global CD uniformity.In our study, CD reduction due to develop loading has a value of a few nm to ~10 nm as a function of flow direction of eroded resist and erosion time resulted from input dose in the photo mask designed to analyze the loading effect using 50keV exposure system.There are limit in reducing the loading effect using rpm or flow amount control in spin spray process. The range, direction and amount of loading effect according to flow direction, erosion time and process condition like rotating speed and chemical flow amount will be discussed, considering E-beam fogging effect. Develop loading effect at puddle process will be presented.