The invention provides an integrated circuit and a manufacturing method thereof and belongs to the semiconductor technical field. The integrated circuit of the invention comprises series-connected transistors and sealed cavities between gates of the series-connected transistors. Low-dielectric insulation between the drains and the gates of the transistors can be realized, and therefore, coupling capacitance between the drains and the gates can be decreased, and the performance of the integrated circuit can be improved. The manufacturing method of an integrated circuit of the invention is used for manufacturing the above integrated circuit; and the manufactured integrated circuit also the above advantages.