A spreader plate for an electronic component cooling assembly has a flat lower surface and a substantially arcuate upper surface of larger surface area than the lower surface which is generally convex and arcuate in cross section, and which decreases in thickness, as measured between the lower and upper surfaces, moving from the central area out to the periphery. This allows the heat flux lines to be more evenly spaced and regular in length, as compared to a typical plate with flat upper and lower surfaces of equal surface area.