Patent ID: 7473631

Claim:
A method of forming a contact hole in a semiconductor device, the method comprising: forming a first insulation layer on an underlying substrate; forming a first conductive layer on a part of the first insulation layer, forming a second insulation layer having a planar, horizontal upper surface on the first insulation layer and the first conductive layer, wherein the planar, horizontal upper surface of the second insulation layer is over both the first insulating layer and the first conductive layer; forming a second conductive layer on a part of the second insulation layer, wherein the second conductive layer does not completely overlap with the first conductive layer; forming a third insulation layer having a planar, horizontal upper surface on the second insulation layer and the second conductive layer, wherein the planar, horizontal upper surface of the third insulation layer is over both the second insulating layer and the second conductive layer; forming a resist having a planar, horizontal upper surface on the third insulation layer; patterning the resist using an exposure mask of which transmittance is different at a first region over the first conductive layer and at a second region over the second conductive layer; and forming a first contact hole and a second contact hole by etching the resist and the third insulation layer using the resist pattern as an etch mask such that the first conductive layer and the second conductive layer are exposed.