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Front side implanted guard ring structure for backside illuminated image sensor

  • US 8,531,565 B2
  • Filed: 02/23/2010
  • Issued: 09/10/2013
  • Est. Priority Date: 02/24/2009
  • Status: Active Grant
First Claim
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1. A method of forming a backside illuminated image sensor, the method comprising:

  • ion-implanting a guard ring structure of a predetermined depth in a front-side surface of a semiconductor substrate, the guard ring structure forming a two-dimensional array of pixels, each pixel of the array of pixels separated from an adjacent pixel by the guard ring structure;

    forming at least one image sensing element on the front-side surface of the semiconductor substrate, the at least one image sensing element being formed in a pixel of the array of pixels and surrounded by the guard ring structure; and

    reducing a thickness of the semiconductor substrate to a predetermined thickness by removing material from the back-side surface of the semiconductor substrate, wherein the thickness of the semiconductor substrate is reduced until the guard ring structure is co-planar with a back-side surface of the semiconductor substrate, whereby the guard ring structure extends from the front-side surface to the back-side surface of the semiconductor substrate having the reduced thickness.

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