DRAM Capacitor Opening Holes Using Sequential Side-Wall Masks

The patent divides the single masking step into multiple sequential masking steps using different mask patterns. First, a first mask pattern is formed to define initial opening regions, then a second mask pattern is formed to define capacitor opening hole positions. This segmentation allows each masking step to focus on specific features, improving the precision of capacitor opening hole formation while enabling higher integration levels through systematic pattern definition.

The patent performs preliminary actions by forming the first mask pattern and first opening regions before forming the second mask pattern and capacitor opening holes. The sacrificial layer is partially removed in advance to create supporting structures that facilitate subsequent precise etching. This preliminary preparation ensures that when capacitor opening holes are formed, the underlying structure is already optimized for high-precision fabrication.

The manufacturing process is segmented into distinct stages: forming first mask pattern and first opening regions, removing sacrificial layer in those regions, forming second mask pattern, and etching capacitor opening holes. This segmentation transforms a complex high-precision process into manageable sequential steps, where each step can be optimized independently, thereby maintaining ease of manufacture while achieving the required precision.

The patent introduces intermediate structures including the first mask pattern, second mask pattern, and partially removed sacrificial layer that serves as a supporting structure. These intermediaries act as mediators that enable precise capacitor opening hole formation without requiring direct complex patterning. The mask patterns serve as intermediaries that translate design requirements into precise physical structures through controlled etching processes.