Method for forming semiconductor substrate

Abstract

A method for forming a semiconductor substrate comprises the steps of providing a silicon substrate comprising a first region and a second region; carrying out ion implantation on the silicon substrate to form an ion implantation layer on the surface of the silicon substrate; forming a mask layer on the surface of the ion implantation layer, wherein an opening is formed in the mask layer above the first region of the silicon substrate; etching the ion implantation layer and the silicon substrate along the opening to form a groove by taking the mask layer as a mask; removing the mask layer; etching the first region of the silicon substrate along the bottom and side walls of the groove to form a cavity; filling the cavity with an oxidation layer. The method for forming the semiconductor substrate of the present invention is simple in technology and low in manufacture cost.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a method for forming a semiconductor substrate. Background technique [0002] A silicon-on-insulator (SOI, SiliconOnInsulator) substrate is a substrate used in integrated circuit manufacturing. Compared with bulk silicon substrates currently widely used, SOI substrates have many advantages: integrated circuits made of semiconductor substrates have small parasitic capacitance, high integration density, small short channel effect, fast speed, and can also realize The dielectric isolation of components in integrated circuits eliminates the parasitic latch-up effect in bulk silicon integrated circuits. [0003] At present, there are two main processes for forming SOI substrates, one of which is the SIMOX (Separation by Implanted Oxygen) process. By implanting oxygen ions into the silicon wafer, oxygen enrichment is formed at a certain depth in the silicon wafer. ...

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Problems solved by technology

[0003] At present, there are two main processes for forming SOI substrates, one of which is the SIMOX (Separation by Implanted Oxygen) process. By implanting oxygen ions into the silicon wafer, oxygen enrichment is formed at a certain depth in the silicon wafer. area, after high-temperature annealing at more than 1300 degrees Celsius, a silicon dioxide oxide layer is formed in the silicon wafer. Due to the limitation of the oxygen ion implantation energy and implantation dose, the adjustable range of the thickness of the oxide layer and the top silicon layer in the silicon wafer is limited. Inflexible, in addition, due to the high annealing temperature, it is difficult to form a large-area SOI substrate; the other is the wafer bonding (WaferBonding) process, which is to combine a silicon wafer with an oxide layer on the surface and another wafer Silicon wafer bonding, and then thinning the back of the silicon wafer to the required thickness to form a silicon-on-insulator technology

However, due to the restriction of silicon wafer thinning technology, the morphology of the formed SOI substrate surface is poor, and the silicon wafer bonding process needs to use two silicon wafers to make an SOI substrate, and the cost is high

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