Vanguard International Semiconductor Corporation

Taiwan Semiconductor Manufacturing Comp. Ltd.

Bi-Ling Chen

Erik S Jeng

Hao-Chieh Liu

Fu-Liang Yang

Chien-Sheng Hsieh

Shih-Ming Chang

Min-Hwa Chi

Chih-Yang Pai

Tzu-Shih Yen

Wei-Ray Lin

Yue-Feng Chen

Ming-Hong Kuo

Wan-Yih Lien

Bih-Tiao Lin

Daniel Hao-Tien Lee

Yu-Chun Ho

Erik S Jerry

A method of fabricating an STI structure comprising the following steps. A silicon structure having a pad oxide layer formed thereover is provided. A hard mask layer is formed over the pad oxide layer. The hard mask layer and the pad oxide layer are patterned to form an opening exposing a portion of the silicon structure. The opening having exposed side walls. A spacer layer is formed over the patterned hard mask layer, the exposed side walls of the opening and lining the opening. The structure is subjected to an STI trench etching process to: (1) remove the spacer layer from over the patterned hard mask layer; form spacers over the side walls; (2) the spacers being formed in-situ from the spacer layer; and (3) etch an STI trench within the silicon structure wherein the spacers serve as masks during at least a portion of time in which the STI trench is formed. The STI trench having corners. Any remaining portion of the spacers are removed. A liner oxide is formed at least within the STI trench whereby the liner oxide has rounded corners proximate the STI trench corners. An STI fill layer is formed over the patterned hard mask layer and filling the liner oxide lined STI trench. The STI fill layer is planarized, stopping on the patterned hard mask layer. The patterned hard mask layer and the patterned pad oxide layer are removed to form a divot-free STI structure having rounded corners.

Method of forming shallow trench isolation with rounded corners and divot-free by using in-situ formed spacers

A method for etching a pattern within a silicon containing dielectric layer upon a substrate employed within a microelectronics fabrication, employing a plasma activated reactive gas mixture, with layer material etch rate, etch rate ratio and pattern aspect ratio controlled by controlling the gas composition. There is provided a silicon substrate formed upon it a patterned microelectronics layer over which is formed a silicon containing dielectric layer. There is placed the silicon substrate within a reactor chamber equipped with electrodes which is evacuated. There is then filled the reactor chamber with a reactive gas mixture consisting of an oxidizing gas and two reactive gases. There may be optionally included in the reactive gas mixture nitrogen and inert gases for control purposes, but excluded from the reactive gas mixture are oxidizing gases containing carbon and oxygen. There is then formed a plasma by supplying high frequency electrical energy to the electrodes within the reactor chamber to bring about a plasma activated reactive gas etching environment, where the conditions may be selected to optimize the desired etch rate and etch rate selectivity.

Etching process

A method for making a novel structure having borderless and self-aligned polysilicon and metal contact landing plugs for multilevel interconnections on integrated circuits is achieved. An etch-stop layer and a planar insulating layer are formed over the devices on a substrate. Contact openings are etched in the insulating layer to the etch-stop layer and the etch-stop layer is removed over the N contact areas. An N doped polysilicon layer is deposited, and second contact openings are etched in the polysilicon and insulating layers over N and P contacts on the substrate to the etch-stop layer. The etch-stop layer is selectively removed and a conducting barrier layer and a metal layer are deposited having a second etch-stop layer on the surface. The layers are patterned to form interconnecting lines and concurrently to form polysilicon landing plugs to the N contacts, while forming metal landing plugs to the N and P contacts. Via holes can now be etched in a second insulating layer over and to the landing plugs. The polysilicon landing plugs to the N contacts reduce current leakage, while the metal contacts to the N and P contacts reduce the contact resistance (Rc). The landing plugs protect the substrate contacts from damage during via hole etch and reduce the aspect ratio for making more reliable contacts.

Method for fabricating borderless and self-aligned polysilicon and metal contact landing plugs for multilevel interconnections

The present invention relates to a method for overcming problems of amplified exposure light interference from shrinked devices and difficulties of photolithographic and etching process control due to multi-level contacts. The present invention combines reflective lights from multiple levels into one single light and reduces interference of reflective lights by introducing a reflective coating and an anti-reflective coating of SiON/Ti or SiON/TiN/Ti which further serve as an etching hard mask for avoiding overetching. The process windows are expanded. Semiconductor devices can be further shrunk and production yields an be improved.

Method for producing multi-level contacts

The practice of forming self-aligned contacts (SACs) in MOSFETs using a silicon nitride gate sidewall and a silicon nitride gate cap has found wide acceptance, particularly in the manufacture of DRAMs, where bitline contacts are formed between two adjacent wordlines, each having a nitride sidewall. The contact etch requires a an RIE etch having a high oxide/nitride selectivity. In order to etch SACs having widths of less than 0.35 microns at their base, such as are encountered in high density DRAMs, special steps must be taken to prevent polymer bridging across the opening which leaves residual insulative material at the base of the contact. The problem is further complicated when the insulative layer through which the opening is formed comprises a silicate glass such as BPSG over a silicon oxide layer. The invention discloses the use of an etchant gas mixture containing octafluorocyclobutane and CH,F in combination with a small but critical concentration of oxygen to etch the SAC opening cleanly and without deleterious erosion of silicon nitride sidewall insulation. The added oxygen prevents polymer bridging across the narrow portion of the SAC.

Method of self-aligned contact hole etching by fluorine-containing discharges

A process for fabricating a DRAM capacitor structure, in which the capacitor upper plate structure is defined during the formation of bit line contact hole opening, and substrate contact hole opening procedure, eliminating the need for a specific upper plate, photolithographic masking procedure, has been developed. The process features isolating a polysilicon upper plate structure, during an isotropic RIE cycle, also creating an undercut polysilicon region, in the contact holes, which are opened simultaneously during the upper plate definition. Subsequent silicon nitride spacers, on the sides of the contact holes, provides insulation between the polysilicon upper plate structure, and bit line, and substrate contact plug structures, now located in the contact holes. The undercut polysilicon regions, allow the formation of thicker silicon nitride spacers, to be formed in this undercut region.

Method of fabricating a capacitor under bit line DRAM structure using contact hole liners

A method for making a novel structure having borderless and self-aligned polysilicon and metal contact landing plugs for multilevel interconnections on integrated circuits is achieved. An etch-stop layer and a planar insulating layer are formed over the devices on a substrate. Contact openings are etched in the insulating layer to the etch-stop layer and the etch-stop layer is removed over the N.sup.- contact areas. An N.sup.+ doped polysilicon layer is deposited, and second contact openings are etched in the polysilicon and insulating layers over N.sup.+ and P.sup.+ contacts on the substrate to the etch-stop layer. The etch-stop layer is selectively removed and a conducting barrier layer and a metal layer are deposited having a second etch-stop layer on the surface. The layers are patterned to form interconnecting lines and concurrently to form polysilicon landing plugs to the N.sup.- contacts, while forming metal landing plugs to the N.sup.+ and P.sup.+ contacts. Via holes can now be etched in a second insulating layer over and to the landing plugs. The polysilicon landing plugs to the N.sup.- contacts reduce current leakage, while the metal contacts to the N.sup.+ and P.sup.+ contacts reduce the contact resistance (Rc). The landing plugs protect the substrate contacts from damage during via hole etch and reduce the aspect ratio for making more reliable contacts.

Method for fabricating borderless and self-aligned polysilicon and metal

A method of removing microscratches in planarized dielectric surfaces covering conductor layers in submicron integrated circuit structures includes a semiconductor substrate having at least one dielectric layer formed thereon followed by a chemical mechanical polishing process for planarization. The removal of microscratches includes depositing a PE-CVD polymer layer to fill the microscratches, caused by CMP planarization, and to cover the planarized dielectric surface with a thin layer of the polymer. Deposition is followed by introducing an etching gas into the CVD chamber for an etch back of the just deposited polymer to well below the depth of the microscratches wherein the deposited polymer has the same etch rate as the dielectric layer formed thereunder.

Method for eliminating CMP induced microscratches

The present invention includes forming a first conductive layer on a semiconductor substrate, and forming a first dielectric layer on the first conductive layer. After patterning to etch the first dielectric layer and the first conductive layer, a second dielectric layer is formed on the semiconductor substrate and the first dielectric layer. Next, the second dielectric layer is anisotropically etched back to form a spacer on sidewalls of the first dielectric layer and the first conductive layer. A first silicon oxide layer is then formed over the semiconductor substrate, the first dielectric layer, and the spacer, followed by forming a photoresist layer on the first silicon oxide layer. A predetermined thickness of the first silicon oxide layer is removed by using the photoresist layer as a mask, and a polymer layer is then formed on the photoresist layer and the first silicon oxide layer. The polymer layer is anisotropically etched back to form a polymer spacer on sidewalls of the photoresist layer and the first silicon oxide layer. The first silicon oxide layer is then anisotropically etched back by using the polymer spacer as a mask to expose surface of the semiconductor substrate, wherein the spacer and the first dielectric layer are used for facilitating self-aligned etching. A second conductive layer is formed over the semiconductor substrate, surface of the second silicon oxide layer being exposed, and a second silicon oxide layer is formed over the second conductive layer and the first silicon oxide layer. Finally, a portion of the second silicon oxide layer is patterned to expose a portion of the second conductive layer, thereby forming the contact hole in the second oxide layer.

Method of forming a contact hole in a semiconductor device

A method for forming multi-level contact holes in a semiconductor structure is disclosed. The semiconductor structure includes a dielectric layer overlying a silicon substrate, a silicon nitride layer within the dielectric layer, the silicon nitride layer overlying a first conductive layer, a silicon oxynitride layer within the dielectric layer, the silicon oxynitride layer overlying a second conductive layer, and a plate poly layer. The method comprises: using a first etching step to etch through the dielectric layer to reach the silicon nitride layer as well as reach the silicon oxynitride layer, the first etching step using a combination of a first gas mixture and a first gas, the first gas mixture comprising a combination of N.sub.2, CO and Ar. The first gas includes C.sub.4 F.sub.8, CH.sub.3 F and O.sub.2, the flow rate ratio of the first gas C.sub.4 F.sub.8 /CH.sub.3 F/O.sub.2 is about 6:1:3. The flow rate of each component of the first gas mixture is that, the flow rate of N.sub.2 is about 0-20 sccm, the flow rate of CO is about 0-200 sccm, and the flow rate of Ar is about 100-600 sccm. In addition, the flow rate of each component of the first gas is that, the flow rate of C.sub.4 F.sub.8 is about 8-40 sccm, the flow rate of CH.sub.3 F is about 1-7 sccm, and the flow rate of O.sub.2 is about 0-20 sccm. Then using a second etching step to etch through the silicon nitride layer to reach the first conductive layer, the second etching step also etching through the silicon oxynitride layer to reach the second conductive layer. The second etching step uses a combination of the first gas mixture and a second gas, the second gas comprising CH.sub.3 F of the flow rate of about 3-14 sccm.

Method for forming multi-level contacts using a H-containing

A method of forming a plurality of contact holes 70 in a semiconductor wafer uses a single step. The semiconductor wafer includes a dielectric layer 69 overlying a silicon substrate 51, a silicon nitride layer 67a, and a silicon oxynitride layer 63c. First, a photoresist 68 layer is developed on the dielectric layer. Prior to forming the dielectric layer, the silicon oxynitride layer is formed overlying a first conductive layer, and the silicon nitride layer is formed overlying a second conductive layer. Second, an etching step is performed to etch through the silicon oxynitride layer, the silicon nitride layer, a portion of the dielectric layer above the silicon oxynitride layer, and the silicon nitride layer to expose the silicon substrate 51, the first conductive layer 63a, and the second conductive layer 67c. The etching recipe includes a first chemistry and a second chemistry. The first chemistry includes C.sub.2 F.sub.6, C.sub.4 F.sub.8, CH.sub.3 F, and Ar. The second chemistry is chosen from a group including O.sub.2, CO.sub.2, CO and any combination thereof. Thus, a plurality of contact holes is formed above the silicon substrate, the first conductive layer and the second conductive layer.

Method for forming multi-level contacts

A method of fabricating contact holes in high density integrated circuits uses landing plugs to reduce the aspect ratio of the the node contact holes in order to improve the processing window of deep contact holes. Along with nitride spacers on the sidewalls of a transistor gate structure, polysilicon hard masks and polysilicon spacers are used as etching masks in a self-aligned contact process. In addition, the landing plugs incorporate the polysilicon spacers as part of landing plug to increase the contact area. As a result, wide contact processing windows can be achieved in high density integrated circuits.

Method of fabricating contact holes in high density integrated circuits

The practice of forming self-aligned contacts in MOSFETs using a silicon nitride gate sidewall and a silicon nitride gate cap has found wide acceptance, particularly in the manufacture of DRAMs, where bitline contacts are formed between two adjacent wordlines, each having a nitride sidewall. The contact etch requires a an RIE etch having a high oxide/nitride selectivity. Current etchants rely upon the formation of a polymer over nitride surfaces which enhances oxide/nitride selectivity. However, for contact widths of less than 0.35 microns, as are encountered in high density DRAMs, the amount of polymer formation required to attain a high selectivity causes the contact opening to close over with polymer before the opening is completely etched. This results in opens or unacceptably resistive contacts. On the other hand, if the etchant is adjusted to produce too little polymer, the nitride cap and sidewalls are thinned or etched through, producing gate to source/drain shorts. The invention describes a two step etching process whereby the contact opening is initially etched at high selectivity, and then, as the contact channel narrows, the polymer formation rate is reduced to prevent polymer pinch off and assure clearance of insulator in the contact area. The method performs both etch steps and the polymer and photoresist removal successively within the same RIE tool.

Two-step etching process for forming self-aligned contacts

A method for creating a DRAM device, featuring the simultaneous formation of a capacitor plate, used for a stacked capacitor structure, and the formation of a metal contact structure, and of a word line contact structure, has been developed. The process features the deposition of a barrier layer, and an overlying tungsten layer, on a storage node electrode, and with the deposition also completely filling a metal contact hole, and a word line hole. A patterning procedure, using an anisotropic RIE procedure, removes unwanted regions of tungsten and barrier layer, resulting in a capacitor plate, a metal contact structure, and a word line structure, all comprised of tungsten and the barrier layers, and all formed via one deposition procedure, and patterned using one RIE procedure.

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Taipei, Taiwan

Bi-Ling Chen