A method of programming a semiconductor memory device includes the steps of grouping memory cells in accordance with levels of threshold voltages to be programmed, programming the memory cell groups by sequentially applying program voltages to the memory cell groups, and program-verifying the memory cell groups. A source of energy is then directed at at least one selected site along the portion of the connective tissue, the amount of energy being sufficient to cause longitudinal shrinkage in the length of connective tissue. A flexible lid 28 is provided which is pivotably coupled to a back portion of the enclosure 12.