Lamp filament having a pitch gradient and method of making

A semiconductor processing chamber comprising:

• a lamp configured to provide heat to an internal volume of the semiconductor processing chamber, the lamp comprising:
• a bulb filled with a gas;
• a filament disposed within the bulb, the filament formed by mixing materials and drawing the materials through a mold to form a wire, and annealing the filament, the filament comprising a plurality of coils, and the plurality of coils comprising:
• a first coil having a first point,
• a second coil having a second point,
• a third coil having a third point, the first, second, and third points forming a pitch gradient, the pitch gradient defined by:
• a first pitch between the second point and the first point, and
• a second pitch between the third point and the second point, wherein the second pitch is greater than the first pitch, the second point is 360 degrees away from the first point, and the third point is 360 degrees away from the second point, and
• a terminal coil electrically coupled to at least the first coil, the second coil, and the third coil.

A method of forming a lamp, the method comprising:

• forming a filament for disposing in a bulb filled with a gas, the filament comprising a plurality of coils, and the forming of the filament comprising mixing materials and drawing the materials through a mold to form a wire;
• forming a pitch gradient between a first coil of the plurality of coils having a first point, a second coil of the plurality of coils having a second point, and a third coil of the plurality of coils having a third point, wherein the pitch gradient is defined by:
• a first pitch between the second point and the first point, and
• a second pitch between the third point and the second point, wherein the second pitch is greater than the first pitch, the second point is 360 degrees away from the first point, and the third point is 360 degrees away from the second point;
• and
• annealing the filament.