Abstract: To prevent a furnace in a semiconductor process from temperature and gas excursion, a paddle and spike thermal couples arranged on the sidewall of the tube and adjacent to the heater, respectively, are connected to a temperature controller to regulate the heater, and a mass controller adjusts the gas flow injected to the tube. In the method, the spike thermal couple, peddle thermal couple and zero point of the mass flow controller are checked to maintain within a first and second temperature ranges and a first gas flow speed range, respectively, and after wafers are loaded and temperature is ramped up, the peddle thermal couple and mass flow controller are checked again to maintain within a third temperature range and second gas flow speed range.

Abstract: A selfaligned process for a flash memory comprises applying a solution with a high etch selectivity to etch the sidewall of the tungsten silicide in the gate structure of the flash memory during a clean process before forming a spacer for the gate structure. This process prevents the gate structure from degradation caused by thermal stress.

Abstract: A selfaligned process for a flash memory comprises applying a solution with a high etch selectivity to etch the sidewall of the tungsten silicide in the gate structure of the flash memory during a clean process before forming a spacer for the gate structure. This process prevents the gate structure from degradation caused by thermal stress.