Wafer-Level Packaging Structure for MEMS Integration

The patent combines the functions of the to-be-packaged wafer, CMOS wafer, and cap wafer into a single integrated wafer structure. The MEMS device, CMOS circuit, and packaging cavity are all formed on one wafer, eliminating the need for separate alignment and bonding of three wafers. This merging approach maintains vacuum packaging quality while dramatically improving production efficiency by reducing the number of processing steps and alignment operations required.

The single wafer structure performs multiple functions simultaneously: it serves as the substrate for the MEMS device, contains the CMOS circuit for signal processing, provides the packaging cavity for vacuum sealing, and acts as the final packaged product. This multi-functionality eliminates the need for separate specialized wafers for each function, reducing cost and improving productivity while maintaining reliability.

The patent merges three separate wafers into one integrated wafer, reducing material costs and processing costs. The single wafer contains all necessary components (MEMS device, CMOS circuit, packaging cavity), eliminating the need for purchasing and processing three separate wafers. This significantly reduces manufacturing cost while maintaining the packaging quality required for vacuum-sealed MEMS devices.

The patent eliminates the need for separate CMOS wafer and cap wafer that would otherwise be discarded after bonding. By integrating all functions into one wafer, the entire wafer can be reused or the full wafer can be diced into multiple packaged devices, maximizing material utilization and reducing waste, thereby lowering manufacturing cost.

The patent segments the complex MEMS device structure into different functional regions within a single wafer. The MEMS device structures, CMOS circuit structures, and packaging cavity are formed in different regions of the same wafer, allowing each region to be optimized independently. This segmentation simplifies the fabrication process by avoiding the need to form all complex structures in one location through multiple complex steps.

The patent utilizes the planar dimension of the wafer to accommodate multiple functional regions simultaneously. Instead of stacking functions vertically across three wafers, all functions are arranged horizontally within the single wafer plane, including MEMS structures in first regions, CMOS circuits in second regions, and packaging cavities in third regions. This dimensional approach simplifies fabrication while maintaining packaging completeness.

The patent segments the wafer into distinct functional regions: first regions for MEMS devices requiring high-temperature processes, second regions for CMOS circuits requiring lower temperatures, and third regions for packaging cavities. This spatial segmentation allows each region to undergo appropriate processing temperatures independently, enabling both high-temperature MEMS formation and CMOS integration on the same wafer platform without mutual interference.

The patent applies local quality by providing different processing conditions to different regions of the wafer. The MEMS regions receive high-temperature processing suitable for their material system, while the CMOS regions receive controlled lower-temperature processing appropriate for their sensitivity. This localized approach to manufacturing enables both types of devices to coexist on the same platform with optimal performance.