Semiconductor Contact Layout for Over-Etch-Free Mixed-Voltage Devices

The patent applies different etch selectivities to different regions by using region-specific etch conditions. Low-voltage devices use a first etch process with higher etch selectivity, while high-voltage devices use a second etch process with lower etch selectivity. This local differentiation allows each region to be etched appropriately without over-etching, thereby improving device reliability while managing process complexity through spatially differentiated treatment.

The patent changes the etch process parameters (etch selectivity, etch rate, process conditions) to achieve differential etching behavior across different device regions. By adjusting these parameters, the patent eliminates the need for additional masking steps while preventing over-etching, thus maintaining device reliability without sacrificing manufacturing throughput and productivity.

The patent performs preliminary actions by forming distinct low-voltage and high-voltage device regions with different structural characteristics before the etching process. The regions are prepared with different gate structures, source/drain configurations, or material compositions that inherently respond differently to etching. This preliminary differentiation enables subsequent etching processes to achieve precise control without requiring extensive additional processing steps, thereby maintaining manufacturing precision while minimizing cycle time.