fig8 a u02dc 8 c show the modified structures of electric connection corresponding to fig7 a 7 c labels 806 a u02dc 806 c are respectively their corresponding added adhesive layers similarly for the structure in the upper figure of fig4 the electric connection between the first adhesive metal layer and the first metal layer can be implemented as three different kinds of structures shown in fig7 a u02dc 7 c also it can further be designed to have the same modification as shown in fig8 a u02dc 8 c fig9 a u02dc 9 c show a b cross sectional views of fig5 to illustrate three different kinds of structures for the electric connection between the first adhesive metal layer and the first metal layer shown in the upper figure of fig4 the same description is not provided herein fig1 a u02dc 10 c show the modified structures of electric connection corresponding to fig9 a u02dc 9 c the same description is not provided herein either according to this invention the top of electrodes 113 a and 113 b and the bonding layer 115 above the second substrate 111 can further be covered by a second metal layer in the structure of the lower figure of fig1 and fig4 fig1 a and 11 b show two different embodiments in fig1 a a second metal layer 1101 is covered on the bonding layer 115 in fig1 b a second metal layer 1103 is covered on electrodes 113 a and 113 b as well as the bonding layer 115 in the structure before bonding when the outmost layers of the first substrate and the second substrate are metal layers covalent bonds will limit free electrons of metal because of the metal.