Contact holes are the regions where electrodes for extracting signals from photosensitive elements of mercury cadmium telluride (MCT) infrared detectors are attached, and the uniformity of their shape and dimensions significantly impacts detector performance. The uniformity achieved by high depth-to-width ratio photolithographic patterning decreases as the distance between the photosensitive elements on the detector chip decreases. In this paper, a method is proposed in which a metal layer is employed as a mask to fabricate contact holes with high uniformity and desirable bottom morphology by thin resist lithography and thin resist etching. The non-uniformity of the contact hole is reduced from 11.54% of the photoresist mask to 5.98% of the metal mask. This approach overcomes the challenge of poor uniformity of the small-pitch HgCdTe chips, which is of reference significance for enhancing the uniformity of the detector signals.