Method for preventing photoetching machine from being stained by metal on back of silicon chip

Abstract

The invention discloses a method for preventing a photoetching machine from being stained by metal on the back of a silicon chip. The method comprises the following steps of: carrying out back cleaning treatment on the silicon chip to be fed into the photoetching machine; placing the silicon chip subjected to cleaning treatment on a temporary tray, wherein silicon is used as a bottom layer material for the temporary tray, a front material used for the temporary tray contains no metal, the temporary tray is provided with a protrusion corresponding to a silicon chip cut and has the following characteristics that the silicon on the back of the silicon chip has extra-high static friction resistance in a direction parallel to the surface of the silicon chip and has no remarkable adhesive power in a direction vertical to the surface of the silicon chip; feeding the silicon chip and the temporary tray into the photoetching machine together; performing spin coating, exposing and developing on a photoresistor; and finally, separating the silicon chip from the temporary tray and performing back cleaning treatment on the back of the silicon chip again. According to the method disclosed by the invention, the photoetching machine is prevented from being stained by the metal on the back of the silicon chip; a front path of silicon chip and a rear path of silicon chip are processed by using the same photoetching machine, so that the capacity is increased; meanwhile, the huge cost for purchasing the new photoetching machine is saved.

Description

technical field [0001] The present invention generally relates to the technical field of semiconductor integrated circuit manufacturing technology, and more precisely, the present invention relates to a method for preventing a photolithography machine from being contaminated by metal on the back of a silicon wafer. Background technique [0002] The main device in integrated circuits, especially VLSIs, is metal-oxide-semiconductor field effect transistors (Metal Oxide Semiconductor Field Effect Transistors, MOS transistors for short), and their geometric dimensions have been shrinking continuously. With the continuous shrinking of the device size, aluminum interconnection has long been replaced by copper interconnection, and the silicide used in the gate has developed from tungsten compound, titanium compound, cobalt compound to nickel compound, metal oxide (Al 2 o 3 , Ta 2 o 5 Wait). The advent of ruthenium as an electroplating seed layer and manganese as a copper barrie...

AI Technical Summary

Problems solved by technology

[0003] At present, there are mainly the following methods in the industry to control metal contamination of lithography machines: one is to reduce the concentration of metal ions on the back of the silicon wafer through a more powerful back cleaning process, but this will cause the consumption of silicon on the back of the silicon wafer, and generally cannot guarantee Reduce the concentration of all metal ions to an acceptable range; the second is to grow a layer of wear-resistant material on the back of the silicon wafer, such as SiN, to isolate metal contamination from silicon and make it stay on the wear-resistant material, and then The wear-resistant material on the back is thinned by chemical mechanical grinding, and finally cleaned to reduce the concentration of metal ions in the silicon on the back of the silicon wafer. However, a layer of 50-300nm SiN is grown on the back, and the furnace tube method will reduce the The thermal budget is increased, and the temperature is too high for the back-end process, which is unacceptable; and the method of chemical vapor deposition will cause scratches on the front of the silicon wafer, thereby affecting the yield; the third is to use the front-end process (relatively high temperature, only gate Metal ions will be introduced in the process) and the subsequent process (relatively low temperature, but various metal ions will be introduced) are carried out in different lithography machines, thus avoiding the metal contamination of the previous high-temperature process in physical space, but reducing The production capacity of the lithography machine is greatly increased based on the price of the lithography machine, which greatly increases the cost of equipment procurement

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