Etching method

Abstract

The invention provides an etching method for improving etching quality. The method comprises the steps of: providing a substrate; forming a shielding layer, a bottom anti-reflection layer and a photoresist layer on the substrate in sequence to form a mask layer; patterning the mask layer; and etching the substrate on the basis of the patterned mask layer.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to an etching method. Background technique [0002] Etching is a common process in the semiconductor manufacturing process, and its principle is: a mask layer is formed on the wafer; based on the mask layer, the wafer is etched. With the development of semiconductor technology, the critical dimensions of devices are shrinking day by day, and the requirements for etching processes are gradually increasing. refer to figure 1 , figure 1 It is a schematic diagram of part of the structure of the control gate of the flash memory in the existing etching process. The etching process in the production process of the control gate (CG, Control Gate) of the flash memory (Flash) based on the 0.18 micron process includes: [0003] A substrate 10 is provided, which includes a first oxide layer (Oxide) 11, a first polysilicon layer (Poly) 12, a dielectric layer (ONO, SiO-SiN-SiO) 13 an...

AI Technical Summary

Problems solved by technology

[0008] For the process of 0.18 microns and below, the PR 152 is too thick in the traditional etching scheme, and there will be the following problems: PR collapse (peeling), that is, the problem of PR collapse due to the excessive thickness of PR during etching, such as figure 2 Shown in the circle; and PR residue (scum), that is, because PR is too thick, PR will remain after development, making the formed PR pattern wrong, such as image 3 circled part

The above two problems will cause etching failure

[0009] In order to solve the above problems, the industry proposes to reduce the thickness of PR 152 for etching, for example, reduce the thickness of PR 152 to 5000 angstroms, and adjust the thickness of BARC 151 to 900 angstroms accordingly, but this can solve the problem of PR peeling and PR scum problem, but there are also the following shortcomings: due to the insufficient thickness of PR 152, it will cause excessive etching, expose BARC 151, damage the polysilicon layer that does not need to be etched away, cause the problem of damage to the edge of the fabricated control gate, and reduce the etching quality ,like Figure 4 circled part

Images