Silicon groove forming method and device

The invention discloses a silicon trough forming method and a device, belonging to the field of semiconductor integration circuit chip process technique. The method of the invention comprises the steps as follows: a hard mask layer grows on the silicon substrate; the surface of the hard mask layer is coated by a photoresist layer; a photoresist pattern is gained by a lithography process; the hard mask layer is etched; the photoresist pattern is copied to the hard mask layer; HBr/CF4/He-O2 mixed gas is introduced into silicon substrate etching equipment so as to etch the silicon substrate and form a silicon trough. The device of the invention comprises a hard mask growth module, a photoresist layer coating module, a hard mask etching module and a silicon substrate etching module. The method and the device of the invention are mainly applied to the etching of the silicon substrate, can improve safety and reduce consumption of HBr, reduce the maintenance cost of the equipment and save the comprehensive consumption cost of the mixed gas.