A forming method of a
metal grid
electrode comprises the following steps: providing a
semiconductor substrate, forming a pseudo grid
electrode on the surface of the substrate, forming an interlayer
dielectric layer on the substrate, allowing the top of the interlayer
dielectric layer to level with the top of the pseudo grid
electrode; utilizing an epitaxial growth to form a first sacrificial layer at least covering the top of the pseudo grid electrode; forming a second sacrificial layer on the interlayer
dielectric layer, allowing the top of the second sacrificial layer to level with the top of the first sacrificial layer; removing the first sacrificial layer, forming an opening inside the second sacrificial layer, and exposing the bottom of the opening outside the top of the pseudo grid electrode; removing the pseudo grid electrode after removing the first sacrificial layer, and forming a grid electrode groove inside the interlayer
dielectric layer; removing the second sacrificial layer, and forming the
metal grid electrode by filling a
metal layer inside the grid electrode groove. By the forming method of the
metal grid electrode, the interlayer
dielectric layer can be well protected from being damaged during the
processing of removing the pseudo grid electrode, without reducing the depth of the grid electrode groove, accordingly the height of the subsequently formed
metal grid electrode is not reduced, thereby increasing the performance of a subsequently formed device.