Method for reducing scratches on surface of polished wafer

Abstract

The invention relates to a method for reducing scratches on the surface of a polished wafer by a polishing machine for an integrated circuit. Through design of a process of taking a ceramic plate polished through a chemical mechanical polishing machine, the process of grabbing a ceramic plate through a mechanical arm of the polishing machine is divided into horizontal pulling action A and vertical grabbing action B; the horizontal pulling action A is composed of the same periodic unit horizontal pulling action a (short for unit action a), and the vertical grabbing action B is composed of n unit vertical pulling actions (short for unit action b) in the vertical direction; the pulling force Fn borne in the unit action b is changed with the pulling frequency n, and the unit action a and the unit action b are alternately carried out to jointly form the overall action for grabbing the ceramic plate, and therefore the total horizontal movement distance S and the total vertical movement distance H in the ceramic plate grabbing process are minimum; and the possibility that polished wafer products are scratched is reduced while the damage of the mechanical arm is reduced.

Description

technical field [0001] This patent belongs to the field of integrated circuits, in particular to the design of a single-step disc removal process in a chemical mechanical polishing machine for single crystal silicon wafers. Background technique [0002] Integrated circuits are the foundation of modern information industry and information society, and also one of the key technologies to promote the development of national economy and informatization, as well as the core technology to transform and revitalize traditional industries. In the manufacturing process of integrated circuits, 90% of semiconductor devices sold in the world are made of silicon materials, and silicon wafers also play a very important role as their basic raw materials. Silicon wafers are produced with polysilicon as raw materials through crystal pulling, slicing, corrosion, heat treatment, polishing, cleaning and other processes. The finished products have the characteristics of complete crystals, high pu...

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Problems solved by technology

Under the existing technology, there are two problems in the polishing process of removing the disk: 1. Since the removing process occurs after the chemical mechanical polishing process, the ceramic disk is tightly adsorbed on the polishing process under the action of pure water and slurry. On the surface of the large plate, it is difficult for the unilateral continuous force to make it break away from the surface of the polished large plate. Therefore, the existing process adopts the method of dragging 20-40mm in the horizontal direction and then pulling in the vertical direction to grab the ceramic plate. The vertical grabbing height The setting value is usually a lifting height of 20-30mm. The pulling force at the moment of pulling up usually uses a force that is more than twice the weight of the ceramic plate itself. However, due to the tight fit between the ceramic plate and the large plate, dragging During the process, it is easy to produce scratches, which will affect the product; 2. Also due to the tight fit between the ceramic plate and the large plate, when the ceramic plate is pulled in the vertical direction to make the ceramic plate separate from the surface of the large plate, the ceramic plate will be due to The reason for the inertia is to quickly rebound in the direction of pulling. This phenomenon has certain damage to the manipulator. Keeping it in this state for a long time will have a certain impact on the accuracy of the manipulator.

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