A back plate includes a substrate, and an insulation layer and a pad group that are located on the substrate. The pad group includes at least two pads. The insulation layer includes openings. The pads protrude towards a side away from the substrate relative to the insulation layer. A mask includes through holes and a blind hole. The orthographic projections of the through holes on the substrate overlap orthographic projections of the pads on the substrate. The blind hole surrounds the through holes. A size of the blind hole in a thickness direction of the mask is greater than or equal to a size of the pad protruding from the insulation layer. An orthographic projection of the blind hole on the substrate and the orthographic projections of the through holes on the substrate after spliced cover the orthographic projections of the pads on the substrate.