Semiconductor Nanostructure Formation with Multi-Patterned GAA Channels

The patent applies segmentation by dividing the single patterning step into multiple sequential patterning steps (double-patterning or multi-patterning). First, a mandrel pattern is formed, then spacers are deposited and patterned, followed by removal of the mandrel, and finally a second pattern is formed. This multi-stage approach enables creation of features at half the pitch of traditional single-step photolithography, directly resolving the contradiction between achieving smaller minimum feature size and maintaining fabrication process simplicity.

The patent employs preliminary action through the use of sacrificial mandrels and spacers that are formed in advance before the final pattern is created. The mandrels are formed first as temporary structures, then spacers are deposited around them, and only after these preliminary structures are in place is the final high-precision pattern achieved. This preliminary structuring enables the subsequent formation of smaller features while managing overall process complexity.

The patent applies self-service through self-aligned spacer formation where the spacer material automatically conforms to the mandrel structure during deposition, creating precisely positioned features without requiring additional alignment steps. The spacer width is determined by the deposition thickness rather than requiring separate lithography alignment, which simplifies the manufacturing process while enabling smaller feature sizes and increased functional density.

The patent utilizes parameter changes by controlling the thickness of deposited spacer layers to precisely define the final feature dimensions. By adjusting deposition parameters (thickness, uniformity, conformality), the process achieves smaller minimum feature sizes while maintaining manufacturing ease. The transition from lateral lithography limitations to vertical deposition control enables scaling to smaller dimensions.