Gradient dry degumming method

Abstract

The invention provides a gradient type dry photoresist removing method. A wafer with photoresist is employed, and the surface of the photoresist is provided with a hard shell which is formed through the injection of high energy particles. The method comprises a step of carrying out pre-heating on the surface of the wafer, a step of softening the hard shell at the surface of the photoresist, a step of removing the hard shell at the surface of the photoresist and leaving the residual photoresist at the surface of the wafer, and a step of removing the residual photoresist. By employing the method of the invention, the photoresist can be effectively removed, the process defects of photoresist burst, residue and polysilicon damage can be avoided, and the yield of products is improved further.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a gradient dry method for degumming. Background technique [0002] In the front-end process of semiconductor wafer production, after photoresist coating, exposure, development and other processes of the wafer, after the high-energy particle implantation, the exposed pattern is the area that needs ion implantation according to the electrical characteristics of the product. A hard crust of a certain thickness is formed on the surface of the area covered by the photoresist. This hard shell is mainly composed of cross-linked carbon chain compounds and doped with various implanted ionic components. This brings more difficulties and challenges to the subsequent degumming process, which is often accompanied by process defects such as residue, popping, and even polybroken, which affects the yield of the product. to negative effects. [0003] In view of the above problems, the p...

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Problems solved by technology

However, in order to prevent poping defects, the process slows down the heating rate by adjusting the distance between the wafer and the heating components, and reduces the reaction rate by reducing the oxygen content. Its main purpose is to slowly remove the hard shell on the surface of the photoresist and reduce defects, but Defect performance is still not ideal in the face of higher dose implant conditions

[0011] In step L03, use CF 4 Reactive gas can effectively remove photoresist (C-Si-O) residues and surface hard shell residues, but it will have other adverse effects on the device

due to CF 4 The gas has strong etching and corrosiveness, which will bring new etching damage to the oxide film or nitride film on the side wall of polysilicon, the silicon or oxide film substrate, and cause the critical dimension of the device or the amount of damage to the substrate silicon. change, which affects the performance of the device

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