| CPC H01L 21/76832 (2013.01) [H01L 21/31116 (2013.01); H01L 21/76805 (2013.01); H01L 21/76807 (2013.01); H01L 21/76831 (2013.01); H01L 21/76877 (2013.01); H01L 21/76897 (2013.01); H01L 23/3171 (2013.01); H01L 23/481 (2013.01); H01L 23/5226 (2013.01); H01L 23/5283 (2013.01); H01L 25/0657 (2013.01)] | 20 Claims | 

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               1. A structure comprising: 
            a first die comprising: 
                a first semiconductor substrate; 
                  a plurality of dielectric layers underlying the first semiconductor substrate; 
                  a plurality of metal rings, each in one of the plurality of dielectric layers; and 
                  a first surface dielectric layer underlying the plurality of metal rings and the plurality of dielectric layers; 
                a second die comprising: 
                a second semiconductor substrate; 
                  a metal pad over the second semiconductor substrate; 
                  a second surface dielectric layer overlying the metal pad, wherein the first surface dielectric layer is bonded to the second surface dielectric layer; 
                a conductive plug penetrating through the first die to contact a top surface of the metal pad; and 
                a first dielectric protection layer encircling and contacting the conductive plug, wherein the first dielectric protection layer is underlying the plurality of metal rings. 
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