Wet Etching and Dry Etching are 2 different substractive manufacturing techniques applied to various fields such as semiconductor, microelectronics, and micromechanical systems (MEMS). Key differences as below:

Medium and Materials:

• Wet Etching: Chemical solutions are usually used to remove materials. These solutions can be acidic or alkaline, depending on the type of material being etched.
• Dry Etching: Gas plasma is used to remove materials. This usually involves physical sputtering or chemical reactions.

Control and Precision:

• Wet Etching: Usually provides lower control and precision.
• Dry Etching: Can provide better control and precision, suitable for manufacturing that requires high precision and complex structures.

Application Areas:

• Wet Etching: Commonly used in mass production, such as etching of silicon wafers.
• Dry Etching: More suitable for manufacturing that requires high precision and complex structures, such as manufacturing of semiconductor devices.

Cost:

• Wet etching: has lower costs because it uses relatively cheap chemical solutions.
• Dry etching: has higher costs because it requires complex equipment and control systems.
  The choice between wet etching and dry etching usually depends on factors such as specific application requirements, cost budget, required accuracy and environmental impact.

Explore more differences here.