Abstract: A submicron semiconductor device having a self-aligned channel stop implant region, and a method for fabricating the semiconductor device using a trim and etch is disclosed. The semiconductor device includes a plurality of active regions separated by insulating regions. The method for fabricating the device includes depositing a nitride over a substrate and selectively covering the active regions with a mask, wherein the mask extends beyond boundaries of the active regions to narrow the width of the insulating regions. Thereafter, a channel stop implant is performed to form channel stops. The mask is then trimmed to the boundaries of the active regions after formation of the channel stops, followed by etching the nitride in exposed areas of the mask. Field oxide is then grown in the insulating regions, whereby the field oxide is self-aligned to the channel stops.

Abstract: A semiconductor process for fabricating NAND type flash memory devices in a first embodiment includes step which can be performed on a production line which manufactures NOR type flash memory products. A NAND flash memory fabrication process according to a second embodiment simplifies the process and uses fewer masks, thus reducing costs and errors to produce higher yields.

Abstract: In one embodiment, the present invention relates to a method of forming a flash memory cell, involving the steps of forming a tunnel oxide on a substrate; forming a first polysilicon layer over the tunnel oxide by chemical vapor deposition using a silicon containing gas and a mixture of a phosphorus containing gas and a carrier gas, the first polysilicon layer having a thickness from about 800 Å to about 1,000 Å; forming an insulating layer over the first polysilicon layer, the insulating layer comprising a first oxide layer over the first polysilicon layer, a nitride layer over the first oxide layer, and a second oxide layer over the nitride layer; forming a second polysilicon layer over the insulating layer; forming a tungsten silicide layer over the second polysilicon layer by chemical vapor deposition using WF6 and SiH2Cl2; etching at least the first polysilicon layer, the second polysilicon layer, the insulating layer, and the tungsten silicide layer thereby defining at least one stacked gate

Abstract: A method of measuring the thickness of a dielectric layer above a plurality of structures of differing types within a semiconductor chip. The method comprises the steps of: forming a plurality of monitor boxes on a semiconductor chip such that each of said plurality of monitor boxes represents a structure type within the semiconductor chip and has substantially the same step height as one of a plurality of differing structure types; forming a dielectric layer over the semiconductor chip; and measuring a thickness of the dielectric layer above at least one of the plurality of monitor boxes, wherein said thickness represents a thickness of the dielectric layer above a structure of the structure type represented by the monitor box. Also disclosed is a semiconductor chip that allows for accurate dielectric thickness measurements.

Abstract: The present invention provides a method for monitoring for a second gate over etch in a flash memory device. The method includes providing at least one select transistor stack structure in the core area of the substrate and at least one monitor structure in the monitor area of the substrate; determining a thickness of a select gate layer of the at least one monitor structure; and determining if a second gate over etch occurred upon the thickness of the select gate layer of the at least one monitor structure. The select gate layer of the monitor structure is the same select gate layer of the select transistor stack structure. The select gate thickness of the select transistor stack structure may be determined by measuring the thickness at the monitor structure. This measurement is possible at the monitor area because the monitor structures are placed far enough apart to support measuring instruments.

Abstract: A method (200) of forming a NAND type flash memory device includes the steps of forming an oxide layer (202) over a substrate (102) and forming a first conductive layer (106) over the oxide layer. The first conductive layer (106) is etched to form a gate structure (107) in a select gate transistor region (105) and a floating gate structure (106a, 106b) in a memory cell region (111). A first insulating layer (110) is then formed over the memory cell region (111) and a second conductive layer (112, 118) is formed over the first insulating layer (110). A word line (122) is patterned in the memory cell region (111) to form a control gate region and source and drain regions (130, 132) are formed in the in the substrate (102) in a region adjacent the word line (122) and in a region adjacent the gate structure (107).

Abstract: The present invention provides a method for reducing the gate aspect ratio of a flash memory device. The method includes forming a tunnel oxide layer on a substrate; forming a polysilicon layer on the tunnel oxide layer; forming an insulating layer on the polysilicon layer; forming a control gate layer on the polysilicon layer; etching at least the tunnel oxide layer, the insulating layer, and the control gate layer to form at least two stack structures; forming a plurality of spacers at sides of the at least two stack structures; and filling at least one gap between the at least two stack structures with an oxide, where the control gate layer provides a gate aspect ratio which allows for a maximum step coverage by the oxide. In a preferred embodiment, the method uses nickel silicide instead of the conventional tungsten silicide in the control gate layers of the cells of the device.

Abstract: Polystringers that cause NAND-type memory core cells to malfunction are covered by ONO fence material. ONO fence is removed so that polystringers may then be removed more readily. A SiON layer, tungsten silicide layer, second polysilicon layer, ONO dielectric, and first polysilicon layer are successively removed from between NAND-type flash memory core cells leaving ONO fence that shields some first polysilicon layer material from removal. The device is next exposed to an hydrogen-fluoride solution to remove oxide-based materials, particularly ONO fence. Thereafter, the polystringers are exposed and may thus be removed more readily.

Abstract: The present invention provides a method for reducing the gate aspect ratio of a flash memory device. The method includes forming a tunnel oxide layer on a substrate; forming a polysilicon layer on the tunnel oxide layer; forming an insulating layer on the polysilicon layer; forming a control gate layer on the polysilicon layer; etching at least the tunnel oxide layer, the insulating layer, and the control gate layer to form at least two stack structures; forming a plurality of spacers at sides of the at least two stack structures; and filling at least one gap between the at least two stack structures with an oxide, where the control gate layer provides a gate aspect ratio which allows for a maximum step coverage by the oxide. In a preferred embodiment, the method uses nickel silicide instead of the conventional tungsten silicide in the control gate layers of the cells of the device.

Abstract: The present invention provides a method for providing an interconnect in a flash memory device. A first embodiment includes forming at least one contact hole in a peripheral area of the device; bombarding a bottom of the at least one contact hole with ions, where the ions break down undesired oxide residing at the bottom of the at least one contact hole; depositing a barrier metal layer into the at least one contact hole, where the barrier metal layer breaks down remaining undesired oxide at the bottom of the at least one contact hole, and where bombarding with the ions and the depositing of the barrier metal layer minimize an undesired widening of the at least one contact hole; and depositing a contact material into the at least one contact hole. With the first embodiment, both the ions and the titanium break down the undesired oxide while neither breaks down the desired oxide at the sides of the contact hole to a significant degree.

Abstract: The present invention provides a method for monitoring for a second gate over etch in a flash memory device. The method includes providing at least one select transistor stack structure in the core area of the substrate and at least one monitor structure in the monitor area of the substrate; determining a thickness of a select gate layer of the at least one monitor structure; and determining if a second gate over etch occurred upon the thickness of the select gate layer of the at least one monitor structure. The select gate layer of the monitor structure is the same select gate layer of the select transistor stack structure. The select gate thickness of the select transistor stack structure may be determined by measuring the thickness at the monitor structure. This measurement is possible at the monitor area because the monitor structures are placed far enough apart to support measuring instruments.

Abstract: A semiconductor device having multiple layers uses different size contacts at different layer in order in order to simply the manufacturing process and the depth of etching required. Contact sizes are selected based on the responsiveness of the material to the etching process. Where a deep etch is required, a larger contact is used. A shallower etch through similar material uses a smaller contact to slow the etching process. As a result, the etches can complete at about the same time. The technique can be employed to etch any number of contacts. An intermediate size contact can be used where the material to be etched results in a slower etching process. A plurality of contact sizes can be used depending on the depths of etching required and the characteristics material to be etched, so that the etching for all the contacts completes at substantially the same time.

Abstract: In one embodiment, the present invention relates to a method of forming a flash memory device involving the steps of forming a gate oxide layer on a substrate; forming a first poly layer over the gate oxide layer; forming an insulating layer over the first poly layer, the insulating layer comprising a first oxide layer over the first poly layer, a nitride layer over the first oxide layer, and a second oxide layer over the nitride layer; forming a second poly layer over the insulating layer; forming a tungsten silicide layer over the second poly layer; etching a portion of the tungsten silicide layer and the second poly layer, wherein in the etched portion at least about 20% of the second poly is not etched, thereby partially defining at least one stacked gate structure; etching at least a portion of the insulating layer and the unetched portion of the second poly layer thereby defining at least one select gate transistor structure; forming an interlayer dielectric layer over the select gate transistor structu

Abstract: A method of depositing metal silicide onto a semiconductor substrate includes a step of depositing, by a CVD process, a first metal silicide layer with silane gas onto the semiconductor substrate. The method also includes a step of thermally treating and chemically cleaning the semiconductor substrate. The method further includes a step of depositing, by the CVD process, a second metal silicide layer with silane gas onto the semiconductor substrate. By this method, cracks in the metal silicide formed on the semiconductor substrate are minimized.

Abstract: This invention relates to a method for removing contaminate nitrogen from the peripheral gate region of a non-volatile memory device during production of said device, wherein at least some of the contaminate nitrogen has formed a bond with the surface of the silicon substrate in contact with the gate oxide layer in said gate region, said method comprising: contacting said gate oxide layer and contaminate nitrogen with a gas comprising ozone at a temperature of about 850° C. to about 950° C. for an effective period of time to break said bond; and removing said gate oxide layer and contaminate nitrogen from said surface of said silicon substrate.

Abstract: A polysilicon-based floating gate is formed so as to be resistant to oxidation that occurs during multiple thermo-cycles in fabrication. Accordingly, edge erase times in NOR-type memory devices may be minimized. Additionally, manufacture of oxidation resistant floating gates reduces variations in edge erase times among multiple NOR-type memory devices. A layer of amorphous silicon is deposited on a silicon substrate by directing silane, a phosphene and helium gas mixture, and ammonia at the surface of the silicon substrate thereby doping the amorphous silicon in situ. The amorphous silicon layer is then etched so as to overlap slightly with regions that will later correspond to the source and drain regions. Next, a lower oxide layer of an ONO dielectric is deposited and the device is heated. A thermo-cycle is eliminated by heating the amorphous silicon during formation of the oxide layer rather than immediately following its deposition.

Abstract: A method of measuring the thickness of a dielectric layer above a plurality of structures of differing types within a semiconductor chip. The method comprises the steps of: forming a plurality of monitor boxes on a semiconductor chip such that each of said plurality of monitor boxes represents a structure type within the semiconductor chip and has substantially the same step height as one of a plurality of differing structure types; forming a dielectric layer over the semiconductor chip; and measuring a thickness of the dielectric layer above at least one of the plurality of monitor boxes, wherein said thickness represents a thickness of the dielectric layer above a structure of the structure type represented by the monitor box.Also disclosed is a semiconductor chip that allows for accurate dielectric thickness measurements.

Abstract: A layer of polysilicon is deposited over an oxide layer on top of a silicon substrate, with core field oxide and active regions, and patterned. An oxide mask is then added. Next, the oxide mask and the layer of polysilicon are removed from above the core field oxide regions. Next, a second layer of polysilicon is deposited and etched to form polysilicon spacers. Later, an ONO dielectric, a third polysilicon layer, a tungsten silicide layer, and SiON layers are successively formed and patterned. The polysilicon spacers effectively seal any recesses that may occur in the edges of the first polysilicon layer to prevent harboring of subsequently added polysilicon material. Accordingly, NAND-type flash memory core cells cannot be electrically shorted by polysilicon material, so called "polystringers", present in such recesses.

Abstract: A method (200) of forming a NAND type flash memory device includes the steps of forming an oxide layer (202) over a substrate (102) and forming a first conductive layer (106) over the oxide layer. The first conductive layer (106) is etched to form a gate structure (107) in a select gate transistor region (105) and a floating gate structure (106a, 106b) in a memory cell region (111). A first insulating layer (110) is then formed over the memory cell region (111) and a second conductive layer (112, 118) is formed over the first insulating layer (110). A word line (122) is patterned in the memory cell region (111) to form a control gate region and source and drain regions (130, 132) are formed in the substrate (102) in a region adjacent the word line (122) and in a region adjacent the gate structure (107).

Abstract: This invention relates to a method for forming a low barrier height oxide layer on the surface of a crystalline silicon substrate, comprising: (A) forming spaced field oxide regions on the surface of said crystalline silicon substrate, the space between said field oxide regions comprising a tunnel region; (B) vapor depositing a layer of amorphous silicon on the surface of said field oxide regions and on the surface of said substrate in said tunnel region, the thickness of said layer of amorphous silicon being in the range of about 50 .ANG. to about 100 .ANG.; and (C) oxidizing said layer of amorphous silicon. The oxidized amorphous silicon layer in said tunnel region is a tunnel oxide layer and, in one embodiment, the inventive method includes the step of (D) forming a floating gate over said tunnel oxide layer, said tunnel oxide layer having a barrier height of about 1.6 to about 2.0 eV.