Promos Technologies, Inc

Other

Jesse Chung

Hsiao-Lei Wang

Sheng-Fen Chiu

Hung-Kwei Liao

Chao-Chueh Wu

Hsio-Lei Wang

A method of forming a buried strap comprising the following sequential steps. A substrate having a pad oxide layer formed thereover is provided. A masking layer is formed over the pad oxide layer. The masking layer, pad oxide layer and substrate are etched to form a trench within the substrate. The trench having an outer sidewall and an upper portion. The upper portion of the trench is lined with a collar. A poly plate is formed within the trench. The poly plate and collar are etched below the substrate to form a recessed poly plate and a recessed collar and exposing a portion of outer sidewall of trench. Ions are implanted into the substrate through exposed outer sidewall of trench by gas phase doping. A SiN sidewall layer is formed over the exposed outer sidewall of trench at a temperature sufficient to diffuse the implanted ions further into the substrate to form the buried strap.

Method of buried strap out-diffusion formation by gas phase doping

A method for manufacturing a deep trench capacitor, which includes forming a layer of silicon nitride over a silicon substrate, depositing a layer of borosilicate glass having a predetermined thickness over the layer of silicon nitride, patterning and defining the layer of borosilicate glass to expose two regions of the silicon substrate separated by a sacrificial mask, wherein the sacrificial mask includes the layer of borosilicate glass and the layer of silicon nitride, etching the two regions of the silicon substrate to form two trenches, wherein the predetermined thickness of the layer of borosilicate glass allows the sacrificial mask and a portion of the silicon substrate beneath the sacrificial mask to be removed, depositing a layer of silicon nitride on the sidewalls of the trenches, and depositing doped polysilicon into the trenches to form a single capacitor.

Method for forming a trench capacitor

A method is achieved for making improved deep trench capacitors for DRAM circuits with reduced trench faceting at the wafer edge and improved pad silicon nitride (Si N ) uniformity for increasing process yields. The method utilizes a thicker pad Si N as part of a hard mask used to etch the deep trenches. Then, after forming the deep trench capacitors by a sequence of process steps a shallow trench isolation (STI) is formed. The method utilizes etching shallow trenches in the same thicker pad Si N layer and into the silicon substrate. A second insulating layer is deposited and polished back (CMP) into the pad Si N layer. A key feature is to use a second mask to protect the substrate center while partially etching back the thicker portion of pad Si N layer at the substrate edge inherently resulting from the CMP. This minimizes the nonuniformity of the pad Si N layer to provide a more reliable structure for further processing.

Method for making deep trench capacitors for DRAMs with reduced faceting at the substrate edge and providing a more uniform pad Si3N4layer across the substrate

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Chu-Pei, Taiwan

Jesse Chung