A method wherein firstly a spacer arrangement and a first wafer are brought together with each other with a first portion of curable adhesive between a first side of the spacer arrangement and the first substrate, to produce a partial stack, and then a second wafer is brought together with a second side of the spacer arrangement, with a second portion of curable adhesive between the second side of the spacer arrangement and the second wafer. Then, the first portion of the curable adhesive and the second portion of the curable adhesive are cured simultaneously.