Monitoring structure and monitoring method for silicon wet etching depth

A method of monitoring silicon wet etching depth, comprising the steps of:

• step one, adding a monitoring pattern to a layout, wherein the monitoring pattern comprises:
• at least two rectangular windows for wet etching;
• widths of the at least two windows are Wu and W1, respectively;
• Wu=du/0.71, W1=d1/0.71;
• du is the maximum wet etching depth to be monitored, d1 is the minimum wet etching depth to be monitored;
• step two, anisotropic wet etching a monocrystalline silicon wafer according to the layout having the monitoring pattern, and forming an etching groove needed to be monitored and a monitoring structure configured to monitor a depth of the etching groove;
• in which, the monitoring structure is formed by etching according to the monitoring pattern, the monitoring structure comprises at least two wet etching grooves with top surface widths of Wu and W1, respectively;
• step three, monitoring the monitoring structure in the step two or after the step two of wet etching, determining an actual etching depth range of the etching groove needed to be monitored according to a monitoring result, thus performing the monitoring of the wet etching depth;
• wherein the step of determining the actual etching depth range of the etching groove needed to be monitored according to the monitoring result comprises:
• when bottoms of the wet etching grooves with top surface widths of Wu and W1 are planar structures, then determining the actual etching depth dactual of the etching grooves needed to be monitored is less than d1;
• when a bottom of the wet etching groove with the top surface width of Wu is a planar structure, while a bottom of the wet etching groove with the top surface width of W1 is a linear structure, then determining the actual etching depth dactual of the etching grooves needed to be monitored is greater than or equal to d1 and less than du;
• and
• when bottoms of the wet etching grooves with top surface widths of Wu and W1 are linear structures, then determining the actual etching depth dactual of the etching grooves needed to be monitored is greater than or equal to du.