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US 9,437,539 B2Granted
Dielectric region in a bulk silicon substrate providing a high-Q passive resonator
AssigneeInternational Business Machines Corporation
InventorsJames S. Dunn, Zhong-Xiang He, Qizhi Liu
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Abstract
Structures and methods of making a dielectric region in a bulk silicon (Si) substrate of a mixed-signal integrated circuit (IC) provide a high-Q passive resonator. Deep trenches within the bulk Si substrate in <100> directions are expanded by wet etching to form contiguous cavities, which are filled by Si oxide to form a dielectric region. The dielectric region enhances the quality (Q) of an overlying passive resonator, formed in metallization layers of the mixed-signal IC.
Claims6
A mixed-signal integrated circuit (IC), comprising:
- a bulk silicon (Si) substrate of a silicon wafer;
- a dielectric region extending down into said bulk Si substrate and having vertical sidewalls that are oriented in <100> directions, according to the Miller index;
- a hard mask including a plurality of holes oriented in said <100> directions, said hard mask overlying said dielectric region;
- a dielectric layer that overlies said hard mask and said dielectric region;
- a high-Q passive resonator formed in metallization layers associated with back-end-of-line (BEOL) processes, said high-Q passive resonator overlying said dielectric region;
- and
- a topmost front-end-of-line (FEOL) layer above said dielectric layer and beneath said high-Q passive resonator formed in said metallization layers.
4 more elements
Dependencies are inferred from the claim text.