An exhaust aftertreatment filter for filtering engine exhaust flowing along an axial direction, said filter being composed of regenerable material regenerated by heat to burn-off trapped contaminant particulate from said engine exhaust, comprising an axially extending cylindrical filter roll having a plurality of concentric layers with pleats therebetween defined by wall segments extending radially in corrugated serpentine manner between pleat tips at axially extending bend lines, said wall segments extending axially between upstream and downstream ends, said wall segments defining axial flow channels therebetween, said wall segments being alternately sealed to each other by a first upstream set of plugs to define a first set of flow channels closed by said plugs, and a second set of flow channels interdigitated with said first set of flow channels and having open upstream ends, said wall segments being alternately sealed to each other by a second downstream set of plugs closing said second set of flow channels, said first set of flow channels having open downstream ends, said flow channels defining cells having an axial length, a radial height, and a circumferentially arcuate width, said cells being tapered between said upstream and downstream ends such that the cross-sectional area of the cell along a plane transverse to said axial direction is larger at one of said ends than at the other of said ends, wherein at least one of said radial height and said arcuate width tapers to a smaller dimension as said flow channel extends axially from said one end to said other end, and wherein said filter roll is spiral-frustoconical-wound from an annular sheet having said corrugated serpentine pleats thereon, said annular sheet having an outer circumference and an inner circumference, said smaller dimension of said at least one of said radial height and said arcuate width being at said inner circumference.