Impurity removal process and manufacturing process of semiconductor monocrystalline silicon wafer

Abstract

The invention discloses an impurity removal process and manufacturing process of a semiconductor monocrystalline silicon wafer, and the impurity removal process comprises the steps: carrying out the heat treatment of the silicon wafer, and forming an oxygen-containing sediment microdefect gettering layer within the thickness range of no more than 20 [mu]m on the surface layer of the silicon wafer, enabling the gettering layer to capture metal impurities on the surface layer of the silicon wafer and in the silicon wafer and removing the metal impurities through polishing. According to the silicon wafer processed by the impurity removal process of the semiconductor monocrystalline silicon wafer, the metal pollution level of the silicon wafer can be effectively reduced, and the surface metal pollution level can be kept stable for a long time.

Description

technical field [0001] The invention belongs to the technical field of semiconductor single crystal silicon, and in particular relates to a process for removing impurities and a manufacturing process of a semiconductor single crystal silicon wafer with a low metal pollution level. Background technique [0002] Single crystal silicon wafer is the main substrate material of modern ultra-large-scale integrated circuits. The ingot obtained by pulling the crystal by the CZ method is manufactured through slicing, chamfering, grinding, corrosion, polishing, cleaning and testing processes to obtain integrated circuit level Semiconductor wafers. With the narrowing of semiconductor line width and the increasingly stringent requirements for dark current of IC components, it is required that the concentration of metal impurities inside the silicon wafer should be as low as possible. In the manufacturing process of silicon wafers, in addition to the purity of the polysilicon raw materia...

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Problems solved by technology

Cleaning and other processes before packaging leave the factory can ensure that the metal pollution level of silicon wafers can meet the requirements. However, in the actual production process, due to the relatively active metals such as copper and nickel, they will migrate to the surface of silicon wafers during the standing process. After the silicon wafers that pass the metal pollution level test are left for a period of time, it is found that the surface metal will increase, and even exceed the specification requirements

[0003] For example, Chinese patent application CN112059736A performs low-temperature annealing before final cleaning to diffuse the metal in the silicon wafer to the surface, and then removes the metal diffused to the surface through the final cleaning process to reduce the level of surface metal pollution. The metal concentration is lower than the metal concentration in the body. If it continues to be placed, the migration and diffusion of metals in the body may still occur, so that the level of metal pollution on the surface cannot be kept stable.

CN109872941A oxidizes the surface of the silicon chip to form an oxide film layer, heats the bottom of the silicon chip at low temperature and irradiates it with microwaves, so that the metal inside the silicon chip diffuses into the oxide film on the surface, and finally the oxide film on the surface of the silicon chip is etched away by an acidic etching solution and the metal adsorbed in it, thereby reducing the metal contamination level of the silicon wafer, but this method requires an additional acid etching cleaning process

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