MEMS Chip and Manufacturing Method Thereof

A manufacturing method of a micro-electro-mechanical-system (MEMS) chip, comprising the steps of:

• making a cap wafer, which includes the steps of:
• providing a first substrate;
• and
• etching a first region of the first substrate to form a plurality of first trenches within the first region, the first region having a first etch pattern density, and concurrently etching a second region of the first substrate to form a plurality of second trenches within the second region, the second region having a second etch pattern density, wherein each of the first trenches and each of the second trenches have substantially a same depth and the first etch pattern density of the first region is higher than the second etch pattern density of the second region;
• making a composite device wafer, wherein the composite device wafer includes a second substrate, and a first MEMS device and a second MEMS device on or above the second substrate;
• and
• bonding the cap wafer and the composite device wafer such that, between the cap wafer and the composite device wafer, a first chamber and a second chamber are formed in correspondence to the locations of the first region and the second region, respectively, wherein the first chamber accommodates the first MEMS device and the second chamber accommodates the second MEMS device.