| 摘要 |
The implementation by photolithography of integrated circuit includes at least one fuse (20) comprising pads (3,4) for electrical contacts and a central region (2) substantially in the form of a bar with a thinner region (21) forming a weak point facilitating the breakdown of fuse element by increasing current density in the conditions of standard breakdown. The method comprises the following steps: the formation of an exposition mask reproducing the fuse design (D20) comprising a central region (D2) in the form of a bar, and artificial elements (D22, D23) in the neighbourhood of central region; the formation of etching mask by exposition for the fuse (20) having the central region (2) with the appearance of a thinner region (21) by the optical effect of proximity, so that the width (W2) of thin region is less than the technological minimum (Wmin) determined by the manufacturing method for integrated circuit. Each artificial element (D22, D23) has an edge (D22-1, D23-1) located with respect to the central region (D2) at a distance (DE3), which is less than the technological threshold (SEmin), below which the optical effect of proximity is manifested. The central region (D2) has a width (DW1) chosen so to obtain the width (W1) of fuse (20) substantially equal to the technological minimum (Wmin). The width (W2) of thin region is substantially equal to half the average width (W1) of central region on the outside of thin zone. The optical effect of proximity forms a progressive thinning of central region, and also transitions of thinning with oblique edges. The thinning is by the formation of notches (21-1, 21-2) on the sides of central region. The etching mask has at least one opening greater than the spacing between elements in the fuse design exposition mask. The etching mask is obtained by the deposition of a layer of photosensitive resin onto a layer of integrated circuit, following an exposition step and a step for the resin removal by a solvent. The fuse of integrated circuit is implemented by the etching of a thin layer of polysilicon, metal or alloy, or by etching of a thin layer formed by a pile of metals or alloys. The fuse of integrated circuit is implemented by polysilicon silicide, with a metal as eg. titanium, cobalt, tungsten, tantalum, and the method includes a step of etching in plasma. The implementation of artificial elements (22,23) favours the etching of an oxide layer on the sides of fuse, so that the fuse has oxide spacers which do not cover entirely the sides of thin zone. |
