Semiconductor Recess Structure for CMP Dishing Prevention
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Solution Overview
Problem
Chemical Mechanical Polishing/Planarization (CMP) techniques often result in dishing, a nonuniform thickness issue, when planarizing structures with wide dimensions such as large metal pads or wide trenches, leading to suboptimal performance and increased manufacturing costs.
Innovation Solution
A semiconductor device and method involving a substrate with an isolation region and a recess, where a first semiconductor material region with a specific conductivity type and doping level is formed alongside a second semiconductor material region, both being distinct and parallel to the substrate surface, with a dishing prevention structure embedded to minimize dishing during planarization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If CMP is used to planarize wide structures, then planarization is achieved, but dishing occurs causing nonuniform thickness
Solution Approach 1:
The patent applies local quality by creating a dishing prevention structure with specific material composition and properties in the regions where dishing is most likely to occur. This structure has different characteristics from the surrounding areas, providing localized protection against dishing while maintaining overall planarization. The selective application of this prevention structure addresses the nonuniform thickness issue without requiring complete process redesign.
Solution Approach 2:
The dishing prevention structure is formed before the CMP process, establishing protective measures in advance. By preparing this structure with appropriate material properties and geometry prior to planarization, the patent prevents dishing from occurring during CMP rather than attempting to correct it afterward. This preliminary action ensures that wide structures maintain uniform thickness throughout the planarization process.
2Manufacturing precision
If dishing prevention structure is added, then dishing is reduced, but device complexity increases
Solution Approach 1:
The patent manages complexity by carefully controlling the parameters of the dishing prevention structure, including its material composition, thickness, and geometric configuration. By optimizing these parameters, the structure provides effective dishing prevention while maintaining compatibility with existing device architectures and fabrication processes. The parameter optimization ensures that the added structure does not unnecessarily complicate the overall device design.
Data Source
AI summary
A semiconductor device is provided. The semiconductor device includes a substrate, an isolation region that is formed at a main surface of the substrate, and a recess in the isolation region. The semiconductor device further includes an active or passive device that is formed in the recess. The active or passive device includes a first semiconductor material region and a second semiconductor material region. The first semiconductor material region adjoins at least part of the second semiconductor material region in a first direction parallel to the main surface of the substrate. An upper surface of the first semiconductor material region is above an upper surface of the second semiconductor material region. The upper surface of the second semiconductor material region is below the main surface of the substrate.