Dummy MIM Capacitor Placement for Etch Loading Balance
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Solution Overview
Problem
Existing semiconductor fabrication methods face challenges in achieving uniform distribution of Metal-Insulator-Metal (MIM) capacitors due to uneven etch loading and mechanical stress, particularly in the presence of through vias that disrupt the placement of dummy MIM structures, leading to suboptimal etch reduction and mechanical strength.
Innovation Solution
A method for inserting dummy MIM structures in isolated regions, accommodating through vias by creating openings that allow the dummy MIM structures to be evenly distributed, ensuring they are spaced apart from adjacent MIM structures and vias, thereby preventing etch loading and mechanical stress issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dummy MIM structures are inserted into isolated regions to reduce etch loading and improve mechanical strength, then the distribution of MIM structures is improved, but the presence of through vias disrupts the placement and prevents even distribution
Solution Approach 1:
The dummy MIM structure is segmented into multiple conductor plate layers (first, second, and third conductor plates) separated by dielectric layers. This segmentation allows the structure to be divided into manageable parts that can be selectively formed and patterned, enabling even distribution around through vias while maintaining etch loading balance and mechanical strength.
Solution Approach 2:
Dielectric layers are introduced as intermediary elements between the conductor plates of the dummy MIM structure. These dielectric layers facilitate the segmentation and allow the dummy structure to be properly integrated into the passivation layer while accommodating through vias, thereby achieving uniform distribution without disruption.
2Productivity
If MIM capacitors are moved to back-end-of-line structures to accommodate scaling, then functional density is increased, but uneven distribution causes nonuniform mechanical strength and etch loading
Solution Approach 1:
The dummy MIM structure is strategically placed in isolated regions of the passivation layer where MIM capacitor distribution is uneven. By providing dummy structures specifically in these localized areas, the patent achieves uniform etch loading and mechanical strength across the entire chip while maintaining high functional density through the selective placement approach.
Data Source
AI summary
An integrated circuit (IC) device according to the present disclosure includes a substrate including a first surface and a second surface opposing the first surface, a redistribution layer disposed over the first surface and including a conductive feature, a passivation structure disposed over the redistribution layer, a metal-insulator-metal (MIM) capacitor embedded in the passivation structure, a dummy MIM feature embedded in the passivation structure and including an opening, a top contact pad over the passivation structure, a contact via extending between the conductive feature and the top contact pad, and a through via extending through the passivation structure and the substrate. The dummy MIM feature is spaced away from the MIM capacitor and the through via extends through the opening of the dummy MIM feature without contacting the dummy MIM feature.