Visible alignment markers/landmarks for CAD-to-silicon backside image alignment
First Claim
1. A metal oxide semiconductor (MOS) integrated circuit (IC), comprising:
- a plurality of fiducial standard cells, wherein the plurality of fiducial standard cells include a plurality of cell sizes, the plurality of cell sizes are non-equally utilized among the plurality of fiducial standard cells, and the plurality of fiducial standard cells are placed to have a random offset from a uniform global placement pattern, wherein each cell size of the plurality of cell sizes of the plurality of fiducial standard cells has one or more openings in a diffusion layer of an active region to allow for reflections of a laser beam from a metal layer.
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Accused Products
Abstract
A metal oxide semiconductor (MOS) integrated circuit (IC) has a plurality of fiducial standard cells of different cell sizes. The different cell sizes are non-equally utilized. The plurality of fiducial standard cells are placed to have a random offset from a uniform global placement pattern. Each of the fiducial standard cells has at least four power rails and various sets of active regions. The power rails extend in a first direction. The active regions are provided adjacent to the power rails but are disconnected from contacts and interconnects and thus do not draw power from the power rails. Instead, the active regions are disjoint and collinear thereby creating islands of active regions among spacings of inactive regions. These inactive regions more easily allow electromagnetic radiation to pass through thereby allowing the MOS fiducial standard cell to be visible for a CAD-to-silicon backside image alignment even with 7 nm feature sizes.
12 Citations
20 Claims
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1. A metal oxide semiconductor (MOS) integrated circuit (IC), comprising:
a plurality of fiducial standard cells, wherein the plurality of fiducial standard cells include a plurality of cell sizes, the plurality of cell sizes are non-equally utilized among the plurality of fiducial standard cells, and the plurality of fiducial standard cells are placed to have a random offset from a uniform global placement pattern, wherein each cell size of the plurality of cell sizes of the plurality of fiducial standard cells has one or more openings in a diffusion layer of an active region to allow for reflections of a laser beam from a metal layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 20)
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19. A method of placing a plurality of fiducial standard cells in a metal oxide semiconductor (MOS) integrated circuit (IC), comprising:
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determining a region of the MOS IC for placing the plurality of fiducial standard cells, wherein the region has an x-direction and a y-direction; subtracting a dither range in the x-direction from one half of a maximum distance in the x-direction between a non-fiducial standard cell and one of the plurality of fiducial standard cells to generate an x-direction half-stepping distance; subtracting a dither range in the y-direction from one half of a maximum distance in the y-direction between a non-fiducial standard cell and one of the plurality of fiducial standard cells to generate a y-direction half-stepping distance; determining a random dither in the x-direction, wherein the random dither in the x-direction ranges from a minus half to a positive half times the dither range in the x-direction; determining a random dither in the y-direction, wherein the random dither in the y-direction ranges from a minus half to a positive half times the dither range in the y-direction; stepping through the x-direction of the region by successively adding twice the x-direction half-stepping distance by the random dither in the x-direction to determine a plurality of placement positions in the x-direction; stepping through the y-direction of the region by successively adding twice the y-direction half-stepping distance by the random dither in the y-direction to determine a plurality of placement positions in the y-direction; and placing the plurality of fiducial standard cells at locations based on the plurality of placement positions in the x-direction and the plurality of placement positions in the y-direction.
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Specification