| 摘要 |
The method includes forming a first insulating layer over a substrate. A first metal layer is formed over the first insulating layer. The first metal layer is patterned to form a plurality of parallel bit lines. A second insulating layer is formed over the bit lines and first insulating layer. At least one via is formed in the second insulating layer. Tungsten fills the via to form a tungsten plug. A second metal layer is formed over the second insulating layer. The second metal layer is patterned to form a plurality of parallel word lines. The word lines and the bit lines crosses at an angle. The present invention is also directed toward a high density ROM device that comprises a substrate and at least one memory array, including a first insulating layer located over a surface of the substrate, and a bit line located on a surface of the first insulating layer. The memory array further includes a second insulating layer formed on a surface of the bit line, and at least one via is formed in the second insulating layer and is in communication with the bit line. Plural word lines are located on a surface of the second insulating layer. The bit lines and the word lines cross at an angle.
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