Donor cores from kerf areas for single-wafer processing
Publication Date: 2014-Feb-26
The IP.com Prior Art Database
Described is the utilization of typically under-used areas on production part-number wafers to yield additional cores for repair or enhancement of the part-number's function.
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Donor cores from kerf areas for single -
In order to improve the overall yield of a semiconductor design, spare parts or "donor" cores are produced and extracted from otherwise unproductive areas of a production part-number wafer. "Donor cores" are extracted from chips which test partially good at wafer final test (WFT) and utilized as shown in Figure 1.
In this invention, donor cores are fabricated on the same wafer as the product/recipient die. On a typical wafer, the product die are evenly spaced and packed together to maximize yield opportunity from the wafer as shown in Figure 2. Further, the reticle will overlap the wafer edges, to create more process stability for adjacent reticle processing by adding "real" devices and wiring to the partial edge reticle exposures. Donor cores are placed in these outer or edge kerf areas of the wafer and/or in between product die-sites.
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The added usage of the kerf areas for donor cores enables "free" additional yield from the wafer, at the minor cost of a few functional product chips. While a single reticle is the typical method of imaging devices on wafers, use of multiple mask sets could clearly allow for various optimization approaches of the base functional chip to "spare" donor core ratios as shown in Figures 3 and 4.
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