A printhead die , comprising: a substrate comprising one or more slotted portions ; wherein each of the one or more slotted portions comprises : a chamber layer formed on the substrate , wherein the chamber layer comprises a void to store printing fluid, wherein the void runs along a length of the corresponding slotted portion ; a plurality of printing fluid ejection chambers coupled to opposite sides of the void and along a length of the chamber layer ; and a top hat layer formed on the chamber layer and the plurality of printing fluid ejection chambers , wherein the top hat layer comprises an unsupported top hat layer portion over the void , wherein an initial portion of the unsupported top hat layer portion has a width across the unsupported top hat layer portion that gradually increases from a first width (w 1 ) at a first end of the initial portion of the unsupported top hat layer portion to a second width (w d ) at a second end of the initial portion of the unsupported top hat layer portion, wherein said first and second ends are separated along the length of the corresponding slotted portion ; characterized in that the top hat layer and the chamber layer are made of the same material; and in that the top hat layer is a photo definable polymer layer thinner than the chamber layer . a substrate comprising one or more slotted portions ; wherein each of the one or more slotted portions comprises : a chamber layer formed on the substrate , wherein the chamber layer comprises a void to store printing fluid, wherein the void runs along a length of the corresponding slotted portion ; a plurality of printing fluid ejection chambers coupled to opposite sides of the void and along a length of the chamber layer ; and a top hat layer formed on the chamber layer and the plurality of printing fluid ejection chambers , wherein the top hat layer comprises an unsupported top hat layer portion over the void , wherein an initial portion of the unsupported top hat layer portion has a width across the unsupported top hat layer portion that gradually increases from a first width (w 1 ) at a first end of the initial portion of the unsupported top hat layer portion to a second width (w d ) at a second end of the initial portion of the unsupported top hat layer portion, wherein said first and second ends are separated along the length of the corresponding slotted portion ; characterized in that the top hat layer and the chamber layer are made of the same material; and in that the top hat layer is a photo definable polymer layer thinner than the chamber layer . a chamber layer formed on the substrate , wherein the chamber layer comprises a void to store printing fluid, wherein the void runs along a length of the corresponding slotted portion ; a plurality of printing fluid ejection chambers coupled to opposite sides of the void and along a length of the chamber layer ; and a top hat layer formed on the chamber layer and the plurality of printing fluid ejection chambers , wherein the top hat layer comprises an unsupported top hat layer portion over the void , wherein an initial portion of the unsupported top hat layer portion has a width across the unsupported top hat layer portion that gradually increases from a first width (w 1 ) at a first end of the initial portion of the unsupported top hat layer portion to a second width (w d ) at a second end of the initial portion of the unsupported top hat layer portion, wherein said first and second ends are separated along the length of the corresponding slotted portion ; characterized in that the top hat layer and the chamber layer are made of the same material; and in that the top hat layer is a photo definable polymer layer thinner than the chamber layer . <EOS>