Patent ID: 7670875

Claim:
A method of manufacturing a single chip semiconductor integrated circuit device comprising a mask read only memory (ROM) and an internal bus to which said mask ROM is connected through metal wires, said method comprising: a) preparing a first semiconductor integrated circuit board comprising a first mask ROM in which a program is not stored and a first internal bus where said first mask ROM is scheduled to be connected through metal wires; b) electrically connecting a programmable ROM independent from said first semiconductor integrated circuit board to said first internal bus with said first mask ROM electrically separated from said first internal bus; c) sealing said first semiconductor integrated circuit board and said programmable ROM in a semiconductor package; d) storing, by using ion implantation, an ultimate program determined by using said programmable ROM in a second mask ROM of a second semiconductor integrated circuit board which is substantially similar in structure to said first semiconductor integrated circuit board; and e) electrically connecting said second mask ROM with a second internal bus in said second semiconductor integrated circuit board by using metal wires.