Various embodiments provide semiconductor devices and fabrication methods. In an exemplary method, a dielectric layer can be formed on a semiconductor substrate. A plurality of pillar structures having a matrix arrangement can be formed on the dielectric layer. A plurality of sidewall spacers can be formed on the dielectric layer. Each sidewall spacer can be formed on a sidewall surface of one of the plurality of pillar structures. A distance between adjacent pillar structures in a same row or in a same column can be less than or equal to a double of a thickness of the each sidewall spacer on the sidewall surface. The plurality of pillar structures can be removed. The dielectric layer can be etched using the plurality of sidewall spacers as an etch mask to form a plurality of trenches or through holes in the dielectric layer.