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 (120, 122) 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 (120, 122) 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 (120, 122) 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.