Manufacturing method of groove type fast recovery diode

The invention discloses a trench type fast recovery diode chip structure and a manufacturing method thereof. The trench type fast recovery diode chip structure is characterized in that an N-drift region is arranged on a heavily doped N + substrate, a P region is arranged in an active region on the N-drift region, and a P + region is arranged on the P region; the surface layer of an active region is provided with mutually parallel longitudinal grooves, the grooves penetrate through a P + layer on the surface layer of the active region and a P layer below the P + layer and then reach an N-layer of a drift region, doped heavy metal such as gold or platinum is distributed in an N-superficial area on the lower side of the bottom of each groove, the grooves are filled with silicon dioxide and polycrystalline silicon, the surface of the chip is provided with a front metal anode electrode, and a back metal anode electrode is arranged on the surface of the chip. And a back metal cathode electrode is connected with the