With regard to etching, it refers to the process of selectively removing unwanted materials from the surface of a silicon wafer by chemical or physical methods. The basic purpose of etching is to correctly replicate the mask pattern on the glued (or masked) silicon wafer.
About etching
Etching refers to the process of selectively removing unwanted materials from the surface of a silicon wafer by chemical or physical methods. The basic purpose of etching is to correctly replicate the mask pattern on the glued (or masked) silicon wafer.
Etching, usually after the photolithography process. We usually leave the desired pattern on the silicon wafer after the photolithography process by etching. From this point of view, etching can be called the final and most important pattern transfer process step. In the usual etching process, the patterned photoresist layer (or mask layer) will not be significantly eroded or etched by the corrosion source, and it can be used as a masking film to protect some special areas on the silicon wafer from being damaged. The photoresist protected areas are selectively etched away.
Introduction to Dry Etching
2.1.2 Dry etching and wet etching
There are two basic etching processes in semiconductor manufacturing: dry etching and wet etching.
Dry etching is to use the plasma generated in the gaseous state to physically and chemically react with the silicon wafer exposed to the plasma through the masking layer window opened by photolithography to etch the exposed surface of the silicon wafer. A process technology method of materials [1]. The outstanding advantage of this process technology is that extremely precise feature patterns can be obtained. The development of ultra-large-scale integrated circuits requires that the microfabrication process can strictly control the processing size, and requires extremely precise pattern transfer on silicon wafers. Any graphics or dimensions that deviate from the process requirements may directly affect product performance or quality and cause irreparable damage to production. Due to the outstanding performance of dry etching technology in pattern shifting, it has become the most important process method for device etching under sub-micron size. In the production of feature patterns, the wet etching technology has been basically replaced.
For wet etching, liquid chemical reagents (such as acids, bases and solvents) are used to chemically remove materials from the surface of the silicon wafer. Of course, when the feature pattern is obtained by wet etching, the exposed surface material should also be etched away through the mask layer window opened by photolithography. However, from the point of view of the accuracy of controlling the shape and size of the pattern, wet etching is generally only used for the larger size (greater than 3 microns) in forming the feature pattern. Due to this feature, wet etching is far less widely used than dry etching. However, due to its high selectivity and batch production mode, wet etching is still widely used in process steps such as etching interlayer films and removing dry etching residues and particles.
