The present invention relates generally to a new apparatus and method for forming cavities in semiconductor substrates without the necessity of using an insert. More particularly, the invention encompasses an apparatus and a method for fabricating cavities in semiconductor substrates wherein a cured thick compressible elastic pad is placed over the cavity prior to lamination and caused to conform to the contour of the cavity, thus preventing collapse of, or damage to, the cavity shelves or corners during the lamination process. After the lamination process, the cured thick compressible elastic pad is conveniently removed from the cavity area without causing any damage to the cavity shelves or corners or having any paste pull-outs. This pad can be reused multiple number of times to form these MLC cavity substrates.