Method of fabricating semiconductor device

A method of fabricating a semiconductor device, comprising:

• preparing a substrate having a first region and a second region;
• forming a first transistor including a first gate electrode and a first source/drain on the first region of the substrate, and forming a second transistor including a second gate electrode and a second source/drain on the second region of the substrate;
• forming a first interlayer insulating layer on the substrate having the first and second transistors;
• forming a conductive pattern passing through the first interlayer insulating layer and electrically connected to the second source/drain;
• forming a second interlayer insulating layer covering the conductive pattern and the first interlayer insulating layer;
• forming a mask on the second interlayer insulating layer;
• performing photolithography and etching processes on the mask to form a first mask opening passing through the mask and exposing the second interlayer insulating layer on the first region, and to form a preliminary mask opening not exposing the second interlayer insulating layer on the second region;
• etching the first and second interlayer insulating layers under the first mask opening without exposing the first source/drain to form a preliminary contact opening passing through the second interlayer insulating layer and extending into the first interlayer insulating layer on the first region;
• etching a mask remaining under the preliminary mask opening, and forming a second mask opening to expose the second interlayer insulating layer under the preliminary mask opening on the second region;
• etching the first interlayer insulating layer remaining between a bottom region of the preliminary contact opening and the first source/drain to form a first contact opening exposing the first source/drain on the first region, and etching the second interlayer insulating layer exposed by the second mask opening to form a second contact opening exposing the conductive layer pattern on the second region;
• and
• removing the mask.

A method of fabricating a semiconductor device having at least first and second electrical contact surfaces and at least one insulation layer on the semiconductor substrate,

• the first electrical contact surface having a depth greater than the second electrical contact surface with respect to an upper surface of the insulation layer, the method comprising:
• etching the at least one insulation layer to form first and second holes in first and second regions of the insulation layer above the first and second electrical contact surfaces, respectively, to expose the first and second electrical contact surfaces,
• the first hole having a planar area larger than the second hole, such that the first hole has a depth greater than the second hole after a same etching process is performed in each of the first and second regions,
• wherein etching the at least one insulation layer includes:
• forming an etching mask on the second insulation layer;
• performing at least a first etching to expose the second insulation layer via the first hole and to form the second hole in the etching mask to not expose the second insulation layer;
• performing at least a second etching to extend the first hole into the first insulation layer without exposing the first electrical contact surface and to extend the second hole to expose the second insulation layer;
• and
• performing at least a third etching to extend each of the first and second holes to expose each of the first and second contact surfaces, respectively.