The rate of wet etching 05

It is usually controlled by changing the concentration and temperature of the solution. The concentration of the solution can change the rate of the reaction material arriving and leaving the surface of the etched material.

In general, the etching rate will increase when the concentration of the solution increases. The increase of the temperature of the solution can accelerate the chemical reaction rate, and then accelerate the etching rate.
In addition to the selection of the solution, it is also very important to choose the suitable shielding material.

It must be well adhered to the surface of the etched material, and can withstand the etching solution erosion and stable and not deteriorate. Optical resistance is usually a good shielding material, and it is often used because its pattern transfer is simple. However, the use of optical resistance as a shielding material also occurs when the edge is stripped or cracked. The edge dissection is caused by the erosion of the etching solution, which results in the difference between the photoresist and the viscosity of the substrate. The solution can use a adhesion promoter to increase the adhesion between the photoresist and the substrate, such as Hexamethyl-disilazane (HMDS). Cracking is due to the difference between the stress difference between the light resistance and the substrate.

The way to slow down the cracking is to absorb the stress difference between the two parts by using the more elastic shielding material.


Nonuniformity produced by etching chemical reaction process of bubbles often caused by etching, the etching solution to prevent the bubble contact retention on the substrate and the etching surface, will make the etching rate slow or stagnant until bubbles leave the substrate surface. So in this case, some catalysts will be added to the solution to enhance the contact between the etching solution and the surface to be etched, and stir it in the process of etching to accelerate the detachment of bubbles.