Method for detecting alignment accuracy
A method for checking with high accuracy the mismatch of two patterns by using a circuit pattern whose change in electrical resistance is highly sensitive to matching shifts. The method includes finding the amount of matching shift of a semiconductor device circuit pattern from the trend in the change in electrical resistance, and comparing the amount of matching shift with the measured value of an overlay measurement mark.
1 . A method of performing alignment accuracy detection of a circuit pattern of a semiconductor device through changes in an electrical resistance of said circuit pattern, the method comprising:
finding an amount of position shift of said circuit pattern from a trend in change of the electrical resistance of said circuit pattern; and
comparing the amount of position shift of said circuit pattern with a measured value of an alignment measurement mark pattern, and thereby finding with high accuracy an amount of mismatch between the circuit pattern and alignment measurement mark pattern.
2 . A method of forming an electrical resistance measurement pattern in a circuit pattern of a semiconductor device, the method comprising:
providing a semiconductor substrate;
forming a first insulation layer on the semiconductor substrate;
forming a first metal wiring in the first insulation layer;
forming a second insulation film over the first insulation layer and the first metal wiring;
forming at least two vias in the second insulation film;
forming a third insulation film over the second insulation film and the at least two vias;
forming a photoresist pattern over the third insulation film;
forming two aperture portions in the photoresist pattern such that the two aperture portions correspond to the at least two vias; and
forming a second metal wiring in the third insulation layer.
3 . The method according to claim 2 , wherein the first insulation layer is formed by a photolithography process, an etching process, and a damascene process.
4 . The method according to claim 2 , wherein the photoresist pattern is formed by a photolithography process.
5 . The method according to claim 2 , wherein a width of each said aperture portion which contacts the associated via is a possibly smallest value.
6 . The method according to claim 2 , wherein the second metal wiring is formed by an etching process and a damascene process.
7 . The method according to claim 2 , wherein the first metal wiring has a spread sufficient for matching tolerance with respect to the at least two vias.
8 . The method according to claim 2 , wherein the at least two vias are formed by a damascene process.