| 摘要 |
PURPOSE:To supply IC provided with various different functions through short manufacturing procedures required for mask ROM programs only by having complated IC, leaving the mask ROM programs only. CONSTITUTION:The title mask ROM is provided with plural basic cells composed of one conductivity type semiconductor substrate 1, a pair of inverse conductivity type regions 5, 6 separately formed on the surface of semiconductor substrate as well as a gate insulating film 8 arranged immediately above the separation part of said regions 5, 6. In such a constitution, any data are written-in by means of selectively irradiating the gate insulating films 8 of basic cells with energy rays for selectively causing damage on positive charge to the gate insulating film 8 of basic cells. In other words, damages fixed by positive charge are caused frequently by means of selectively irradiating the gate insulating film 8 formed immediately above the channel forming region with short wave beams or soft X-rays. At this time, any data are written-in by means of depleting or enhancing the channel region by the functions of positive charge. Through these procedures, the processes required after writtingin the data until the delivery thereof can be reduced markedly shortening the delivery term notably compared with the conventional delivery term. |
