EMICONDUCTOR DEVICE

PURPOSE:To prevent information obtd. from an initial user from being leaked while reducing the cost of a microcomputer or the like by providing the semiconductor device of the single chip microcomputer or the like capable of turning a built-in mask ROM to a use disable state without performing any b...

Ausführliche Beschreibung

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Bibliographische Detailangaben
Hauptverfasser:	HASHIMOTO KOICHIRO, TOTANI TATSURO, SHIBUKAWA YOSHIMICHI, SUZUKAWA KAZUFUMI, SHINAGAWA YUTAKA
Format:	Patent
Sprache:	eng
Schlagworte:	CALCULATING COMPUTING COUNTING ELECTRIC DIGITAL DATA PROCESSING ELECTRICITY PHYSICS
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Beschreibung
Zusammenfassung:	PURPOSE:To prevent information obtd. from an initial user from being leaked while reducing the cost of a microcomputer or the like by providing the semiconductor device of the single chip microcomputer or the like capable of turning a built-in mask ROM to a use disable state without performing any bonding processing. CONSTITUTION:The activating part ROMS of a read only memory ROM composed of a mask ROM is provided with a start control MOSFETCN 1 for selectively changing the threshold voltage by selectively performing ion injection after a protection film at least the upper part of the channel is partially removed or thinned previously and the protection film is formed. By selectively turning on this start control MOSFETCN 1, a start control signal ROME to the read only memory ROM is selectively made invalid.