3D high resolution X-ray sensor with integrated scintillator grid

摘要

Various embodiments of a 3D high resolution X-ray sensor are described. In one aspect, an indirect X-ray sensor includes a silicon wafer that includes an array of photodiodes thereon with each of the photodiodes having a contact on a front side of the silicon wafer and self-aligned with a respective grid hole of an array of grid holes that are on a back side of the silicon wafer. Each of the grid holes is filled with a scintillator configured to convert beams of X-ray into light. The indirect X-ray sensor also includes one or more silicon dies with an array of photo-sensing circuits each of which including a contact at a top surface of the one or more silicon dies. Contact on each of the photodiodes is aligned and bonded to contact of a respective photo-sensing circuit of the array of photo-sensing circuits of the one or more silicon dies.

主权项

1. A method of constructing a photo-die of an X-ray sensor, comprising:
forming an oxide layer on a first side of a silicon wafer; forming an array of grid holes on a second side of the silicon wafer opposite the first side thereof; filling the grid holes with an oxide; forming an array of photodiodes on the first side of the silicon wafer by implanting the first side of the silicon wafer with p-type impurities and n-type impurities such that each photodiode of the array of photodiodes is aligned with a respective grid hole of the array grid holes; depositing a thin nitride layer on the first side of the silicon wafer; removing the oxide in the grid holes; coating sidewalls of the grid holes with an insulator stack; filling the grid holes with a scintillator material; heating the silicon wafer to crystallize the scintillator material; forming a multilevel metal stack over the photodiodes on the first side of the silicon wafer; and forming a plurality of metal pillars that are electrically connected to the photodiodes through the multilevel metal stack.