This invention provides an interposer for electrically connecting two substrates with high density interconnections. The interposer comprises an elastomeric material surrounding fine metal wires which extend through the elastomeric material. The elastomeric material provides mechanical support and electrical isolation for the wires which connect the two opposing surfaces of the interposer with mating substrates. One surface of the interposed has scribes cut into it which mechanically isolate the individual wires. This mechanical isolation between wires reduces the stress placed on the substrates from being connected when the interposer is compressed between the substrates. The support given individual wires by the elastomeric material is controlled, by adjusting the spacing and widths of the scribes, to provide uniform compression across the substrates. Reducing the differentials in compression across the substrates reduces the stress on the substrates and their connections, and therefore, maintains substrate reliability when the substrates are exposed to extended time periods under compression.