Abstract: A method for fabricating a novel plug structure for low resistance ohmic stacked contacts and at the same time forming metal contacts to devices on a SRAM cell was achieved. The method involved forming electrically conductive plugs in the stacked contact openings to form ohmic connections between a P+ doped polysilicon layer and a N+ doped polysilicon layer and thereby increasing the on current (Ion) of the SRAM cell. The electrical conductive plugs are also simultaneously formed in metal contact openings to devices areas elsewhere on the substrate. The process for the plug structure also reduces the mask set by one masking level over the prior art process.

Abstract: A method of providing a chemical mechanical polishing planarization process for preventing multi-polysilicon and multi-metal level electrical shorts, which includes briefly the sequential processing steps of i) providing an insulating layer to a first thickness over a device wafer with non-planar surface topography; ii) chemical-mechanical polishing the first insulating layer; and iii) deposition of another polysilicon layer of second thickness to prevent the barely exposed or exposed underlying polysilicon from shorting to the next polysilicon or metal level of interconnects.

Abstract: A process for forming HSG polysilicon has been developed. The process features initially depositing an amorphous silicon layer, at a temperature between about 490 to 550.degree. C. The amorphous silicon layer is then subjected to an in situ anneal procedure, at a temperature between about 600 to 650.degree. C., and at a pressure between about 0.5 to 1.5 mTorr, for about 30 min, to convert the amorphous silicon layer to a HSG polysilicon layer. The surface roughness of the HSG polysilicon, when used as the top layer of a storage node structure, of a stacked capacitor structure, results in a surface area increase of about 50%, thus offering increases in capacitance.

Abstract: A method for providing a chemical mechanical polishing planarization process for preventing multi-polysilicon and multi-metal level electrical shorts, which includes briefly the sequential processing steps of i) providing an insulating layer to a first thickness over a device wafer with non-planar surface topography; ii) chemical-mechanical polishing the first insulating layer; and iii) deposition of another polysilicon layer of second thickness to prevent the barely exposed or exposed underlying polysilicon from shorting to the next polysilicon or metal level of interconnects.

Abstract: A three dimensional polysilicon resistor and a method by which the three dimensional polysilicon resistor is manufactured. A semiconductor substrate has formed upon its surface an insulating layer. The insulating layer has a minimum of one aperture formed at least partially through the insulating layer. A polysilicon layer is formed upon the insulating layer and formed conformally into the aperture(s) within the insulating layer. The polysilicon layer is then patterned to form a resistor which includes the portion of the polysilicon layer which resides within the aperture(s).

Abstract: A process for forming an HSG silicon layer, to be used as a component of, as well as to increase the surface area of, a polysilicon storage node electrode, has been developed. The process features initially depositing a polysilicon composite, comprised of underlying, undoped polysilicon layer, and an overlying, doped polysilicon silicon layer, resulting in an initial degree of surface roughness. The process continues with the deposition of an amorphous silicon layer, and an in situ anneal procedure, resulting in the conversion of the amorphous silicon layer, to a HSG silicon layer. The storage node electrode is then formed, comprised of the roughened HSG silicon layer, overlying the polysilicon composite.

Abstract: A fabrication process for integrating stacked capacitor, DRAM devices, and thin film transistor, SRAM devices, has been developed. The fabrication process features combining key operations used to create transfer gate transistor structures, and access transistor structures for the DRAM and SRAM devices. In addition, process steps, used to create a capacitor structure, for the DRAM device, and a thin film transistor structure, for the SRAM device, are also shared. Another key feature of this invention is a buried contact structure, used for the SRAM device.

Abstract: A fabrication process for integrating stacked capacitor, DRAM devices, and thin film transistor, SRAM devices, has been developed. The fabrication process features combining key operations used to create transfer gate transistor structures, and access transistor structures for the DRAM and SRAM devices. In addition, process steps, used to create a capacitor structure, for the DRAM device, and a thin film transistor structure, for the SRAM device, are also shared. Another key feature of this invention is a buried contact structure, used for the SRAM device.

Abstract: A method for fabricating buried metal plug structures for multi-polysilicon layer interconnects and for concurrently making metal plugs on semiconductor integrated circuits, such as DRAM and SRAM, was achieved. The method involved forming contact opening in an insulating layer over opening in a patterned polysilicon layer. The opening in the polysilicon layer aligned over source/drain contact areas on the substrate and providing a means for forming self-aligned contact openings. Buried metal plugs in the contact openings form interconnects between the polysilicon layer and the source/drains. And, by merging the process steps, concurrently forming metal plug interconnects for contacts to semiconductor devices and first level metal. The process is applicable to the formation of bit line contacts on DRAM and SRAM circuits and simultaneously form the peripheral contact on the chip.

Abstract: Reduced area metal contacts to a thin polysilicon layer contact structure having low ohmic resistance was achieved. The structure involves forming contact openings in an insulating layer over a buffer layer composed of a thick polysilicon layer. A portion of the sidewall in the opening includes a patterned thin polysilicon layer that forms part of a semiconductor device and also forms the electrical connection to the metal contact. The structure provides metal contacts having very low resistance and reduced area for increased device packing densities. The metal contact structure also eliminates the problem of forming P.sup.+ /N.sup.+ non-ohmic junctions usually associated with making P.sup.+ /N.sup.+ stacked contact. The structure further allows process steps to be used that provide larger latitude in etching the contact opening and thereby provides a structure that is very manufacturable.

Abstract: A method is provide for a unified stacked contact structure which concurrently forms all the polysilicon interconnects and the polysilicon load resistors on a SRAM device. FETs formed from a first polysilicon layer are coated with a first insulating layer. A second polysilicon layer is deposited and patterned forming portions of the SRAM circuit and concurrently forming openings over FET source/drain areas. A second insulating layer is deposited, and contact openings are selectively etched in the insulating layer over the openings in the second polysilicon layer. The exposed second polysilicon layer in the contacts serve as an etch mask for etching the first insulating layer to the source/drain contact areas, thereby forming contacts self-aligned to the openings in the second polysilicon layer. The contact openings in the node contact areas also expose portions of the gate electrodes .of the SRAM driver transistors.

Abstract: A method for fabricating buried metal plug structures for multi-polysilicon layer interconnects and for concurrently making metal plugs on semiconductor integrated circuits, such as DRAM and SRAM, was achieved. The method involved forming contact opening in an insulating layer over opening in a patterned polysilicon layer. The opening in the polysilicon layer aligned over source/drain contact areas on the substrate and providing a means for forming self-aligned contact openings. Buried metal plugs in the contact openings form interconnects between the polysilicon layer and the source/drains. And, by merging the process steps, concurrently forming metal plug interconnects for contacts to semiconductor devices and first level metal. The process is applicable to the formation of bit line contacts on DRAM and SRAM circuits and simultaneously form the peripheral contact on the chip.

Abstract: A multi-layer polysilicon resistor and a method by which the multi-layer polysilicon resistor is formed. A minimum of two polysilicon layers is formed upon an insulating layer, the insulating layer in turn being formed upon a semiconductor substrate. The first polysilicon layer is formed to a first thickness at a first deposition temperature. The second polysilicon layer is formed directly upon the first polysilicon layer. The second polysilicon layer is formed to a second thickness at a second deposition temperature. The two deposition temperatures are in the range of about 450 degrees centigrade to about 620 degrees centigrade, and the difference in temperature between the first deposition temperature and the second deposition temperature is a minimum of 10 degrees centigrade.

Abstract: A method for fabricating a novel plug structure for low resistance ohmic stacked contacts and at the same time forming metal contacts to devices on a SRAM cell was achieved. The method involved forming electrically conductive plugs in the stacked contact openings to form ohmic connections between a P+ doped polysilicon layer and a N+ doped polysilicon layer and thereby increasing the on current (I.sub.on) of the SRAM cell. The electrical conductive plugs are also simultaneously formed in metal contact openings to devices areas elsewhere on the substrate. The process for the plug structure also reduces the mask set by one masking level over the prior art process.

Abstract: A method for fabricating a novel plug structure for low resistance ohmic stacked contacts and at the same time forming metal contacts to devices on a SRAM cell was achieved. The method involved forming electrically conductive plugs in the stacked contact openings to form ohmic connections between a P+ doped polysilicon layer and a N+ doped polysilicon layer and thereby increasing the on current (I.sub.on) of the SRAM cell. The electrical conductive plugs are also simultaneously formed in metal contact openings to devices areas elsewhere on the substrate.

Abstract: A method was achieved for making a static random access memory SRAM by integrating or merging into the SRAM process a unified contact plug process that reduces the number of processing steps and forms low resistance ohmic contacts between N.sup.+ and P.sup.+ polysilicon layers. The plug process utilizes patterned features in the multi-layers of polysilicon and the high selective etching of silicon oxide to polysilicon to form all the contact concurrently, and thereby eliminate the need to etch contacts openings between each polysilicon layer. The unified contact plug method was demonstrate on the SRAM for making the a buried contacts for the node contacts on the SRAM, the bit line contacts and a V.sub.ss contact for the ground plane in the SRAM cell.

Abstract: A novel method is presented for making an array of stacked capacitors on DRAM circuits. Chemical/Mechanical Polishing (CMP) is used to form "globally" a very planar surface on an insulating layer across the substrate. By virtue of this global planarization three additional insulating layers deposited consecutively thereon, also provide a very planar surface for exposing and developing high fidelity (distortion free) photoresist images. Subsequent anisotropic plasma etching of deposited layers on these planar surfaces also provide residue free (strings) structures. Stacked capacitors are then fabricated by etching contact openings in the insulating layers to the source/drain areas of FETs on the substrate. Alternate insulating layers having different etch rates are isotropic wet etched in the contact openings to recess and form fin-shaped profiles in the openings sidewalls.

Abstract: A method for fabricating reduced area metal contacts to a thin polysilicon layer contact structure having low ohmic resistance was achieved. The method involves forming contact openings in an insulating layer over a buffer layer composed of a thick polysilicon layer. A portion of the sidewall in the opening includes a patterned thin polysilicon layer that forms part of a semiconductor device and also forms the electrical connection to the metal contact. The method provides metal contacts having very low resistance and reduced area for increased device packing densities. The metal contact structure also eliminates the problem of forming P.sup.+ /N.sup.+ non-ohmic junctions usually associated with making P.sup.+ /N.sup.+ stacked contact. The method further allows large latitude in etching the contact opening and thereby provides a very manufacturable process.

Abstract: A method for forming a metal contact in a self aligned contact region over a impurity region in a substrate which comprises forming a doped polysilicon layer over the device surface except in a contact area. A thin polysilicon barrier layer and a metal layer, preferably tungsten, are then formed over the polysilicon layer and the contact area. The resulting metal contact has superior step coverage, lower resistivity, and maintains the shallow junction depth of buried impurity regions.