Method of forming a tungsten plug in a semiconductor device

Claim 1

A method of forming a tungsten plug in a semiconductor device in which lower metal lines and upper metal lines are connected through a via hole which is formed by etching some portions of an insulating film in a semiconductor device, the method comprising: A. sequentially forming a barrier metal layer and a tungsten layer on said insulating film including said via hole; B. forming, on the tungsten layer in the upper side of the via hole, a photoresist pattern of which size is enough to cover said via hole; C. firstly etching said tungsten layer by an isotropic etching process using said photoresist pattern as an etch mask; D. secondly etching the firstly-etched tungsten layer by an anisotropic etching process using said photoresist pattern as an etch mask so that the barrier layer is exposed; and E. after said photoresist mask is removed, removing the projections of said tungsten layer which are created on the upper portion of said via hole as a result of said isotropic etching process and said anisotropic etching process, whereby forming a tungsten plug within said via hole.

Claim 2

A method of forming a tungsten plug in a semiconductor device in which lower metal lines and upper metal lines are connected through a via hole which is formed by etching some portions of an insulating film in a semiconductor device, the method comprising: A. sequentially forming a barrier metal layer and a tungsten layer on said insulating film including said via hole; B. forming, on the tungsten layer in the upper side of the via hole, a photoresist pattern of which size is enough to cover said via hole; C. firstly etching said tungsten layer by an isotropic etching process using said photoresist pattern as an etch mask; D. secondly etching the firstly-etched tungsten layer by an anisotropic etching process using said photoresist pattern as an etch mask so that the barrier layer is exposed; and E. after said photoresist mask is removed, removing the projections of said tungsten layer which are created on the upper portion of said via hole as a result of said isotropic etching process and said anisotropic etching process, whereby forming a tungsten plug within said via hole.

Claim 8

A method of forming a tungsten plug in a semiconductor device in which lower metal lines and upper lines are connected through via hole which is formed by etching some portion of an insulating film in a semiconductor device, the method comprising: A. sequentially forming a barrier metal layer and a tungsten layer on said insulating film including said via hole; B. forming, on said tungsten layer in an upper side of the via hole, a photoresist pattern having a large size which is large enough to cover said via hole; C. firstly etching said tungsten layer by an isotropic etching process using the photoresist pattern as an etch mask; D. after the photoresist mask is removed, etching the firstly-etched tungsten layer by an anisotropic etching process until said barrier metal layer is exposed, thereby forming a tungsten plug within said via hole.

Claim 9

A method of forming a tungsten plug in a semiconductor device in which lower metal lines and upper lines are connected through via hole which is formed by etching some portion of an insulating film in a semiconductor device, the method comprising: A. sequentially forming a barrier metal layer and a tungsten layer on said insulating film including said via hole; B. forming, on said tungsten layer in an upper side of the via hole, a photoresist pattern having a large size which is large enough to cover said via hole; C. firstly etching said tungsten layer by an isotropic etching process using the photoresist pattern as an etch mask; D. after the photoresist mask is removed, etching the firstly-etched tungsten layer by an anisotropic etching process until said barrier metal layer is exposed, thereby forming a tungsten plug within said via hole.