Wet etching method

A wet etching method, comprising:

• providing a substrate, wherein a layer to-be-etched is on a surface of the substrate;
• and
• performing a plurality of etching treatments on the layer to-be-etched till a thickness of the layer to-be-etched reaches a target thickness, wherein each etching treatment includes:
• performing a first etching process, wherein in the first etching process, the substrate is at a first rotation speed;
• after the first etching process, performing a second etching process, wherein in the second etching process, a rotation speed of the substrate is reduced from the first rotation speed to a second rotation speed, a liquid film of a chemical solution on the surface of the substrate is increased to a first thickness, and the chemical solution contains an organic acid including acetic acid, oxalic acid, or a combination thereof;
• and
• after the second etching process, performing a third etching process, wherein the substrate is at a third rotation speed, and the third rotation speed is lower than or equal to the first rotation speed.

A wet etching method, comprising:

• providing a substrate, wherein a layer to-be-etched is on a surface of the substrate;
• and
• performing a plurality of etching treatments on the layer to-be-etched till a thickness of the layer to-be-etched reaches a target thickness, wherein each etching treatment includes:
• performing a first etching process, wherein in the first etching process, the substrate is at a first rotation speed;
• after the first etching process, performing a second etching process, wherein in the second etching process, a rotation speed of the substrate is reduced from the first rotation speed to a second rotation speed, a liquid film of a chemical solution on the surface of the substrate is increased to a first thickness, and in the second etching process, a unit time period is provided, and the rotation speed of the substrate is reduced by 100 revolutions per minute in the unit time period;
• and
• after the second etching process, performing a third etching process, wherein the substrate is at a third rotation speed, and the third rotation speed is lower than or equal to the first rotation speed.