Shielding techniques for an integrated circuit
View Patent ↗Described herein are techniques for forming, during wafer processing, a conductive shielding layer for a chip formed from a wafer. The conductive shielding layer can be formed on multiple sides of a chip prior to dicing the wafer to separate the chip from the wafer. A wafer may be processed to form trenches that extend substantially through the wafer. The trenches may be formed opposite scribe lines that identify boundaries between chips of the wafer and may extend through the wafer toward the scribe lines. A shielding layer may be formed along the trenches.
1. A method of forming at least one conductive shielding layer for an integrated circuit, the integrated circuit to be formed from a first region of a wafer, the wafer comprising a second region from which a second integrated circuit is to be formed and a boundary region between the first region and the second region, the method comprising:
forming the at least one conductive shielding layer on at least three sides of the first region while the first region is a part of the wafer, the forming comprising:
forming a second conductive layer on a first surface of the wafer, the second conductive layer extending between the first region and the second region across the boundary region, the second conductive layer forming a portion of the at least one conductive shielding layer on a first side of the first region;
forming a trench in the boundary region, the trench extending from a second surface of the wafer opposite the first surface of the wafer and through the wafer, wherein the second conductive layer extends between the first region and the second region across the boundary region following formation of the trench; and
forming a third conductive layer on the second surface of the wafer, the third conductive layer forming a portion of the at least one conductive shielding layer on at least a second side and a third side of the first region.
2. The method of claim 1 , wherein forming the at least one conductive shielding layer comprises forming the at least one conductive shielding layer on at least five sides of the first region prior to separating the integrated circuit from the wafer.
3. The method of claim 1 , further comprising:
dicing the wafer to separate the integrated circuit from the wafer.
4. The method of claim 1 , wherein forming the trench comprises forming the trench extending through a majority of the wafer.
5. The method of claim 1 , wherein, during the forming of the trench, the second conductive layer is exposed on the first surface of the wafer.
6. The method of claim 1 , further comprising:
after forming the third conductive layer, separating the first region from the wafer at the trench.
7. The method of claim 6 , wherein separating the first region from the wafer comprises cutting a remainder of the wafer along the trench, wherein cutting the remainder of the wafer comprises cutting the second conductive layer.
8. The method of claim 1 , wherein forming the trench comprises forming the trench surrounding the first region.
9. A method for processing a wafer, the wafer including a region corresponding to a chip to be formed from the wafer, the method comprising:
forming, adjacent to the region, a trench in the wafer extending through a majority of a thickness of the wafer;
forming a conductive shielding layer for the integrated circuit along a side of the trench; and
after forming the shielding layer, cutting through the trench to separate the chip from the wafer,
wherein the wafer includes on a first side a scribe line marking edges of the region, the scribe line comprising a conductive layer, and
wherein forming the trench comprises forming the trench on a second side of the wafer, opposite from the first side, extending substantially through the wafer to the conductive layer.
10. The method of claim 1 , wherein forming the third conductive layer comprises forming the third conductive layer with at least a portion of the third conductive layer that is formed in the trench contacting the second conductive layer.
11. The method of claim 1 , wherein forming the trench through the wafer comprises forming the trench through the wafer to the second conductive layer, wherein at least a portion of the second conductive layer is exposed on the second surface of the wafer following the forming of the trench.