1. Field of the Invention
The present invention is related to a semiconductor memory device.
2. Description of the Related Art
A semiconductor memory device which is manufactured using a semiconductor includes a region in which memory elements are arranged and a region in which peripheral circuits are arranged. Also, most of the region in which peripheral circuits are arranged is taken up with analog circuits. In an analog circuit, resistance elements are used. Resistance elements are, for example, arranged being concentrated around input terminals of signals, which are externally input.
In addition, within a semiconductor memory device which comprises a NAND type flash memory, highly accurate resistance elements are required in a limiter circuit, for example, for accurately converting a high voltage generated by a charge pump circuit to a predetermined voltage. In addition, an RC delay circuit which is one type of analog circuit is comprised using resistance elements and highly accurate resistance elements are also required for an RC delay circuit.
The resistance elements of a semiconductor memory device are formed by a semiconductor formation process. For example, a technology for changing the resistance value of a resistance element is disclosed in Japan Laid Open Patent 2006-269504, in which a plurality of contacts separated by equal intervals along the length of a resistance element are formed and a wiring pattern which is connected with one of the contacts and the value of the resistance element is changed thereby.