Abstract:
A Top Oxide Method is used to form an oxide layer over an array of vertical transistors as in a trench dynamic random access memory (DRAM) array with vertically stacked access metal oxide semiconductor field effect transistors (MOSFETs). The Top Oxide is formed by first forming the vertical devices with the pad nitride (16) remaining in place. Once the devices have been formed and the gate polysilicon (18) has been planarized down to the surface of the pad nitride, the pad nitride is stripped away leaving the tops of the gate polysilicon plugs extending above the active silicon surface. This pattern of polysilicon plugs defines the pattern over which the Top Oxide is deposited. The deposited Top Oxide (21) fills the regions between and on top of the polysilicon plugs. The Top Oxide is than planarized back to the tops of the polysilicon plugs so contacts can be made between the passing interconnects and the gates of the vertical devices. The Top Oxide layer serves to separate the passing interconnects from the active silicon thereby reducing capacitive coupling between the two levels and providing a robust etch-stop layer for the reactive ion etch (RIE) patterning of the subsequent interconnect level.
Abstract:
A high density plasma deposition process for eliminating or reducing a zipper-like profile of opened-up voids in a poly trench fill by controlling separation between a transfer gate and storage node in a vertical DRAM, comprising: etching a recess or trench into poly Si of a semiconductor chip; forming a pattern of SiN liner using a mask transfer process for formation of a single sided strap design; removing the SiN liner and etching adjacent collar oxide away from a top part of the trench; depositing a high density plasma (HDP) polysilicon layer in the trench by flowing either SiH4 or SiH4 + H2 in an inert ambient; employing a photores ist in the trench and removing the high density plasma polysilicon layer from a top surface of the semiconductor to avoid shorting in the gate conductor either by spinning on resist and subsequent chemical mechanical polishing or chemical mechanical downstream etchback of the polysilicon layer; and stripping the photoresist and depositing a top trench oxide by high density plasma.
Abstract:
A method for forming metallizations for semiconductor devices, in accordance with the present invention, includes forming trenches (107) in a dielectric layer (104), depositing a single layer diffusion barrier (116) in the trenches, and without an air-brake, depositing a seed layer (118) of metal on the surface of the diffusion barrier. The trenches are then filled with metal (120). The metal adheres to the seed layer, which adheres to the diffusion barrier to provide many improvements in electrical characteristics as well as to reduce failures in the semiconductor devices.
Abstract:
A method of providing isolation between element regions of a semiconductor memory device (200). Isolation trenches (211) are filled using several sequential anisotropic insulating material (216/226/230) HPD-CVD deposition processes, with each deposition process being followed by an isotropic etch back to remove the insulating material (216/226/230) from the isolation trench (211) sidewalls. A nitride liner (225) may be deposited after isolation trench (211) formation. A top portion of the nitride liner (225) may be removed prior to the deposition of the top insulating material (230) layer.
Abstract:
The invention provides a trench storage structure that includes a substrate having a trench, a capacitor conductor in the lower part of the trench, a conductive node strap in the trench adjacent the capacitor conductor, a trench top oxide above the capacitor conductor, and a conductive buried strap in the substrate adjacent the trench top oxide. The trench top oxide includes a doped trench top oxide layer above the conductive strap, and an undoped trench top oxide layer above the doped trench top oxide layer.
Abstract:
Disclosed is a method of simultaneously supplying trench isolations for array and support areas of a semiconductor substrate made of a substrate material, the method comprising providing a first hard mask layer for the array and support areas, said first hard mask comprising mask openings defining trench isolations in the array and support areas, providing deep array trench isolations in the array areas, providing a blanketing planarized conductive material layer over both support and array areas sufficient to fill said mask openings and deep array trench isolations, etching said conductive material through said first hard mask material down into said semiconductor substrate so as to form support trench isolations, such that both deep array trench isolations and support trench isolations are of equal depth, and wherein a conductive element, comprising a quantity of said conductive material, remains in the bottom of each of said deep array trenches.
Abstract:
A trench isolation structure is formed in a substrate. One or more openings are formed in a surface of the substrate, and a liner layer is deposited at least along a bottom and sidewalls of the openings. A layer of doped oxide material is deposited at least in the openings, and the substrate is annealed to reflow the layer of doped oxide material. Only a portion near the surface of the substrate is removed from the layer of doped oxide material in the opening. A cap layer is deposited atop a remaining portion of the layer of doped oxide material in the opening.
Abstract:
The invention provides a trench storage structure that includes a substrate having a trench, a capacitor conductor in the lower part of the trench, a conductive node strap in the trench adjacent the capacitor conductor, a trench top oxide above the capacitor conductor, and a conductive buried strap in the substrate adjacent the trench top oxide. The trench top oxide includes a doped trench top oxide layer above the conductive strap, and an undoped trench top oxide layer above the doped trench top oxide layer.
Abstract:
CMP of integrated circuits containing DRAM arrays with trench capacitors fill the trenches with oxide, resulting in a an array of oxide structures that is dense compared with the concentration in the surrounding support structures and therefore has a higher loading. A conformal layer is deposited over the wafer, increasing the loading in the array, but filling in spaces between active areas. A blanket etch removes material in both the array and the supports. A block etch balances the amount of material in the array and the supports. A supplementary oxide deposition in the array fills spaces between the structures to a nearly uniform density.