| 摘要 |
A method for forming a metal line of a semiconductor device is provided to restrain a reverse taper type structure from being generated at a sidewall of the metal line and to prevent the misalignment between the metal line and a lower via by controlling properly a flow rate of plasma gas and plasma generating power. An insulating layer(120), a metal film, and a photoresist pattern(210) are sequentially formed on a semiconductor substrate. A main etching process is performed on the resultant structure by etching selectively the metal film using the photoresist pattern as an etch mask. At this time, a taper type metal line(141) is formed on the resultant structure. An over etching process is performed on the resultant structure. A first flow rate of Cl2: BCl3: Ar under the main etching process is in a predetermined range of 2: 1: 1.2 to 2: 1: 1.4. A second flow rate of Cl2: BCl3: Ar under the over etching process is in a predetermined range of 3: 4: 4.5 to 3: 4: 5.5. The power rates between upper and lower electrodes in the main etching process and the over etching process are in predetermined ranges of 4: 1 to 5: 1.
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