Test structure and calibration method

摘要

A test structure for measuring a Micro-Electro-Mechanical System (MEMS) cavity height structure and calibration method. The method includes forming a sacrificial cavity material over a plurality of electrodes and forming an opening into the sacrificial cavity material. The method further includes forming a transparent or substantially transparent material in the opening to form a transparent or substantially transparent window. The method further includes tuning a thickness of the sacrificial cavity material based on measurements obtained through the transparent or substantially transparent window.

主权项

1. A method comprising:
forming a first sacrificial cavity material over a plurality of electrodes; planarizing the first sacrificial cavity material; forming a second sacrificial cavity material on the planarized first sacrificial cavity material; patterning the first and second sacrificial cavity materials to form an opening aligned with an underlying electrode of the plurality of electrodes; forming a transparent or substantially transparent material over the first and second sacrificial cavity materials including within the opening and over the underlying electrode; patterning the transparent or substantially transparent material to form a transparent or substantially transparent window within the first and second sacrificial cavity materials; polishing an upper surface of the second sacrificial cavity material and remaining portions of the transparent or substantially transparent material formed in additional patterned areas of the first and second sacrificial cavity materials; prior to form a Micro-Electro-Mechanical System (MEMS) beam, measuring a thickness of the first and second sacrificial cavity materials from a top surface to the underlying electrode through the opening in the first and second sacrificial cavity materials and which is obtained through the transparent or substantially transparent window; and tuning the thickness of the first and second sacrificial cavity materials after the measuring, the tuning includes depositing additional sacrificial cavity material on the second sacrificial cavity material.