摘要:
A method for making a self-aligned isolated flash memory core without damaging tunnel oxide layers between memory element stacks and the silicon substrate supporting the stacks includes depositing three sidewall layers on the stacks, prior to etching isolation trenches between the stacks, to thereby shield the tunnel oxide during isolation trench etching.
摘要:
A wet etching process for establishing isolation grooves in a flash memory core wafer includes depositing nitride and/or oxide layers on a silicon substrate of the wafer, depositing a photoresist layer thereon, and then exposing predetermined portions of the photoresist layer to ultraviolet light to establish a desired groove pattern in the photoresist layer. A dry etching process is then used to remove the nitride and/or oxide layers beneath the groove pattern of the photoresist layer to thereby expose portions of the substrate. Next, the wafer is disposed in a wet etching solution such as potassium hydroxide to form grooves in the exposed portions of the silicon substrate. The wafer is oriented and disposed in the bath as appropriate for forming V-shaped grooves, such that after etching, the angled walls of the grooves can be easily exposed to a dopant beam directly above the wafer, without having to tilt the wafer or beam source. Thereby, the walls of the grooves are easily implanted with dopant.
摘要:
A method is provided of forming lines with spaces between memory cells below a minimum printing dimension of a photolithographic tool set. In one aspect of the invention, lines and spaces are formed in a first polysilicon layer that forms floating gates of flash memory cells. STI regions are formed between adjacent memory cells in a substrate to isolate the cells from one another. The first polysilicon layer is deposited over the substrate covering the STI regions. The first polysilicon layer is then planarized by a CMP process or the like to eliminate overlay issues associated with the STI regions. A hard mask layer is deposited over the first polysilicon layer and a first space dimension d1 etched between adjacent memory cells. A conformal nitride layer is deposited over the hard mask layer and an etch step performed to form nitride side walls adjacent the spaces. The nitride side walls reduce the first space dimension to a second space dimension d2, so that spaces can be formed in the first polysilicon layer at a dimension smaller than the minimum printable dimension of the photolithographic tool set.
摘要:
A method for forming a memory device is provided. A nitride layer is formed over a substrate. The nitride layer and the substrate are etched to form a trench. The nitride layer is trimmed on opposite sides of the trench to widen the trench within the nitride layer. The trench is filled with an oxide material. The nitride layer is stripped from the memory device, forming a mesa above the trench.
摘要:
A method for forming a memory device is provided. A nitride layer is formed over a substrate. The nitride layer and the substrate are etched to form a trench. The nitride layer is trimmed on opposite sides of the trench to widen the trench within the nitride layer. The trench is filled with an oxide material. The nitride layer is stripped from the memory device, forming a mesa above the trench.
摘要:
A memory device includes a substrate and a first dielectric layer formed over the substrate. At least two charge storage elements are formed over the first dielectric layer. The substrate and the first dielectric layer include a shallow trench filled with an oxide material. The oxide material formed in a center portion of the shallow trench is removed to provide a region with a substantially rectangular cross-section.
摘要:
A memory device is provided including a substrate. A first dielectric layer is formed over the substrate. An isolation trench is formed in a portion of the substrate and the first dielectric layer. At least two charge storage elements are formed over the first dielectric layer on opposite sides of the isolation trench. A second dielectric layer is formed over the at least two charge storage elements. A control gate layer is formed over the second dielectric layer, where the isolation trench has a width suitable for reducing cross-coupling noise of charge storage elements, and where the at least two charge storage elements have a height suitable for providing sufficient gate coupling between the at least two charge storage elements and the control gate layer.
摘要:
A method for forming a memory device includes forming a hard mask over a substrate, where the hard mask includes a first mask layer and a second mask layer formed over the first mask layer. The substrate is etched to form a trench. The trench is filled with a field oxide material. The second mask layer is stripped from the memory device using a first etching technique and the first mask layer is stripped from the memory device using a second etching technique, where the second etching technique is different than the first etching technique.
摘要:
A method for providing at least one contact on a semiconductor is disclosed. The semiconductor includes a plurality of isolation structures. The method and system include providing an etch-stop layer in direct contact with the semiconductor, providing a dielectric layer over the etch-stop layer, and etching through the dielectric layer and a portion of the etch-stop layer. A portion of the semiconductor in proximity with one of the plurality of isolation structures is not exposed during the etch.
摘要:
A method is disclosed for the definition of the poly-1 layer in a semiconductor wafer. A non-critical mask is used to recess field oxides in the periphery prior to poly-1 deposition by an amount equal to the final poly-1 thickness. A complimentary non-critical mask is used to permit CMP of the core to expose the tops of core oxide mesas from the shallow isolation trenches.