The HDC3021 has a polyimide tape to cover the opening of the humidity sensor element. The tape protects the humidity sensor element from pollutants that can be produced as part of the manufacturing process, such as SMT assembly, printed circuit board (PCB) wash, and conformal coating. The tape must be removed after the final stages of assembly for accurate measurement of relative humidity in the ambient environment. The tape can withstand at least three standard reflow cycles.
To remove the polyimide tape from the humidity sensor element, TI recommends to use a ESD-safe tweezer to grip the adhesive-free tab in the top right corner, and slowly peel the adhesive from the top-right corner towards the bottom-left corner in an upward direction (as opposed to across the surface). This will help to reduce the risk of scratching the humidity sensor element.