Stepped Through-Hole Openings for Multi-Layer Insulating Stacks

The patent divides the through hole formation process into multiple sequential etching steps, each targeting a specific insulating layer. The first etching step forms a first through hole through the first insulating layer, the second etching step forms a second through hole through the second insulating layer, and the third etching step forms a third through hole through the third insulating layer. This segmentation allows each etching process to be optimized for its specific layer thickness and material composition, preventing defects that would occur if all layers were etched simultaneously.

The patent performs preliminary actions by forming protective structures and guiding layers before the etching process. A protective layer is formed on the metal composite structure before etching the insulating layers. Additionally, guiding layers are formed to define the etching patterns. These preliminary structures protect the metal composite structure from damage during etching and ensure precise alignment of the through holes across multiple layers, preventing breakage of insulating layers.

The patent applies local quality by using different etching conditions for different insulating layers. Each insulating layer (first, second, and third) has different material composition and thickness, so the etching process is locally optimized for each layer. The first etching step uses parameters suited for the first insulating layer, the second etching step uses parameters for the second layer, and so on. This local optimization allows the device to maintain enhanced functionality with diverse insulating materials while making the manufacturing process manageable through step-specific parameter adjustment.

The patent changes etching parameters between different etching steps to match the specific characteristics of each insulating layer. The etching conditions (such as etchant concentration, temperature, time, and power) are adjusted according to the material composition and thickness of each layer. This parameter adaptation enables successful etching of through holes through multi-layer insulating structures with varying properties, making the manufacturing of functionally enhanced devices feasible.