TWI456699B - Bit line structure and method for manufacturing the same - Google Patents

Claims (11)

A method for fabricating a bit line structure, comprising: providing a substrate; forming a bottle-shaped trench in the substrate, wherein the bottle-shaped trench comprises a first trench and an enlarged second trench, and The first trench and the second trench each have a first sidewall and a second sidewall facing each other, and the first sidewalls of the first and second trenches are located in the bottle-shaped trench Forming an insulating layer to fill the second trench, covering the first and second sidewalls and the bottom of the second trench; forming a first opening facing the first trench in the insulating layer Removing a portion of the insulating layer adjacent to a top portion of the first sidewall of the second trench from the first opening to form a second opening, the second opening connecting the first opening and exposing the first a top portion of the first sidewall of the trench; filling a conductive material in the second opening; and forming a wire at a bottom of the bottle-shaped trench, the wire being in direct contact with the conductive material. The method for manufacturing a bit line structure according to claim 1, wherein the step of forming the bottle-shaped trench comprises: forming the first trench in the substrate; forming a first protective layer lining The first and the second sidewalls of the first trench; etching the bottom of the first trench to form the second trench. Manufacturing of the bit line structure as described in claim 1 The method, wherein removing a portion of the insulating layer from a top portion of a first sidewall of the second trench from the first opening comprises: filling the conductive material in the first opening; forming a second a protective layer and a third protective layer, wherein the second protective layer is lined on the first and second sidewalls of the first trench, and wherein the third protective layer covers the second protective layer And extending into the second trench; forming a sacrificial layer on the conductive material; selectively removing the third protective layer adjacent to the first sidewall; and the third protection on the second sidewall The layer is a mask that removes a portion of the insulating layer adjacent the top portion of the first sidewall of the second trench. The method for manufacturing a bit line structure according to claim 3, wherein the step of filling the conductive material in the second opening comprises: forming the conductive material in the bottle-shaped groove; and removing The conductive material is a portion other than the second opening. The method for manufacturing a bit line structure according to claim 4, further comprising removing the third surface on the second sidewall before forming the conductive material in the second trench and the second opening The protective layer. The method for manufacturing a bit line structure according to claim 4, further comprising removing the second protective layer after removing the conductive material. The method for manufacturing a bit line structure according to claim 3, wherein the step of selectively removing the third protective layer adjacent to the first sidewall comprises: Depositing an amorphous phase germanium layer covering at least a portion of the third protective layer above the sacrificial layer on the second sidewall; the amorphous phase polycrystalline germanium is implanted toward the second sidewall The layer is doped; the undoped portion of the amorphous phase germanium layer is removed; and the third protective layer is removed adjacent to the first sidewall. The method of fabricating a bit line structure according to claim 1, wherein the wire extends into the second opening. A bit line structure comprising: a substrate having a bottle-shaped groove therein, wherein the bottle-shaped groove comprises a first groove and an enlarged second groove, wherein the second groove is compared to The first trench has a widened portion, and the first trench and the second trench each have a first sidewall and a second sidewall facing each other, and the first and second trenches The first sidewall is located on the same side of the bottle-shaped trench; an insulating layer is disposed in the second trench, and has a first opening facing the first trench and a second trench and a second trench An opening, the second opening is connected to the first opening and exposing a top portion of the first sidewall of the second trench, wherein the insulating layer substantially fills the second trench except the second opening The widened portion; a conductive material at least in a portion of the substrate adjacent to the second opening; and a wire disposed in the first opening and in direct contact with the conductive material. The bit line structure as described in claim 9 of the patent scope, wherein The wire extends into the second opening. The bit line structure of claim 9, wherein the conductive material has a portion located in the second opening.