摘要:
A process for reducing the aspect ratio, for narrow diameter contact holes, formed in thick insulator layers, used to integrate logic and DRAM memory devices, on the same semiconductor chip, has been developed. The process of reducing the aspect ratio, of these contact holes, features initially forming, via patterning procedures, lower, narrow diameter contact holes, to active device regions, in the logic area, while also forming self-aligned contact openings to source/drain regions in the DRAM memory region. After forming tungsten structures, in the lower, narrow diameter contact holes, polycide bitline, and polysilicon capacitor structures, are formed in the DRAM memory region, via deposition, and patterning, of upper level insulator layers, and polysilicon and polycide conductive layers. Upper, narrow diameter openings, are then formed in the upper level insulator layers, exposing the top surface of tungsten structures, located in the lower, narrow diameter contact holes. The formation of upper tungsten structures, in the upper, narrow diameter contact openings completes the process of forming metal structures, in narrow diameter openings, with reduced aspect ratios, achieved via a two stage contact hole opening, and a two stage metal filling procedure.
摘要:
A method using a two-step contact process for making word-line strapping on DRAM devices was achieved. The method replaces a single-step contact process in which it is difficult to etch the smaller contact openings. After partially completing the DRAM cells by forming gate electrodes and word lines having a first hard mask, a planar first insulating layer is formed. Capacitor node contact openings are etched and capacitors with a protective second hard mask are completed. A thin first photoresist mask with improved resolution is used to etch small first contact openings in the first insulating layer to the word lines, while the second hard mask protects the capacitors from etching. Tungsten plugs are formed in the openings, and an interlevel dielectric layer is deposited over the capacitors. A thin second photoresist mask with improved resolution is used to etch second contact openings to the tungsten plugs. The word-line strapping for the DRAM is completed by forming tungsten plugs in the second contact openings. Since the tungsten plugs are formed after forming the capacitors, they are not subjected to high-temperature processing that could adversely affect the DRAM devices. The two thin photoresist masks replacing a thicker photoresist mask used in the single-step process allow smaller contact openings to be etched.
摘要:
A method for making crown capacitors using a new and improved crown etch window process for DRAM cells is described. After forming FETs for the memory cells, a planar first insulating layer (IPO-1) is formed and bit lines are formed thereon. A second insulating layer (IPO-2) is deposited, and a first etch-stop layer and a disposable insulating layer are deposited. Contact openings are etched in the layers to the substrate, and are filled with a polysilicon to form capacitor node contact plugs. The disposable layer is removed to expose the upper portions of the plugs extending above the first etch-stop layer. A second etch-stop layer is deposited and a thick insulating layer is deposited in which capacitor openings are etched over and to the plugs. The capacitor openings can be over-etched in the thick insulating layer because the plugs extend upward thereby allowing all the plugs to be exposed across the wafer without overetching the underlying IPO-2 layer that would otherwise cause capacitor-to-bit-line shorts when the bottom electrodes are formed in the capacitor openings.
摘要:
A method using a single masking step for making double-cylinder stacked capacitors for DRAMs which increases capacitance while eliminating erosion of an underlying oxide insulating layer when the masking step is misaligned is described. A planar silicon oxide (SiO2) first insulating layer is formed over device areas, and a first silicon nitride (Si3N4) etch-stop layer is deposited, and openings are etched for capacitor node contacts. A first polysilicon layer is deposited to a thickness sufficient to fill the openings and to form an essentially planar surface. A second insulating layer is deposited and patterned to form portions with vertical sidewalls over the node contacts. A conformal second Si3N4 layer is deposited and etched back to form spacers on the vertical sidewalls, and the first polysilicon layer is etched to the first Si3N4 layer. The second insulating layer is selectively removed using HF acid while the first polysilicon and first Si3N4 layers prevent etching of the underlying first SiO2 layer. A second polysilicon layer is deposited and etched back to form double-cylinder sidewalls for the capacitor bottom electrodes. The first and second Si3N4 layers are removed in hot phosphoric acid. The capacitors are completed by forming an interelectrode dielectric layer on the bottom electrodes, and depositing a third polysilicon layer for top electrodes.
摘要翻译:描述了一种使用单个掩模步骤来制造用于DRAM的双圆柱体堆叠电容器的方法,其在掩蔽步骤未对准时消除了下面的氧化物绝缘层的侵蚀,同时增加了电容。 在器件区域上形成平面氧化硅(SiO 2)第一绝缘层,并沉积第一氮化硅(Si 3 N 4)蚀刻停止层,并且蚀刻用于电容器节点接触的开口。 第一多晶硅层被沉积到足以填充开口并形成基本平坦的表面的厚度。 沉积和图案化第二绝缘层以在节点接触件上形成具有垂直侧壁的部分。 沉积保形第二Si 3 N 4层并回蚀刻以在垂直侧壁上形成间隔物,并且将第一多晶硅层蚀刻到第一Si 3 N 4层。 使用HF酸选择性地除去第二绝缘层,而第一多晶硅和第一Si 3 N 4层防止蚀刻下面的第一SiO 2层。 沉积第二多晶硅层并将其回蚀以形成用于电容器底部电极的双气缸侧壁。 在热磷酸中除去第一和第二Si 3 N 4层。 电容器通过在底部电极上形成电极间电介质层而形成,并且为顶部电极沉积第三多晶硅层。
摘要:
A new method of depositing PE-oxide or PE-TEOS. An HDP-oxide is provided over a pattern of polysilicon. An etch back is performed to the deposited HDP-oxide, a layer of plasma-enhanced SiN is deposited. This PE-SiN is etched back leaving SiN spacers on the sidewalls of the poly pattern, further leaving a deposition of HDP-oxide on the top surface of the poly pattern. The profile of the holes within the poly pattern in such that the final layer of PE-oxide or PE-TEOS is deposited without resulting in the formation of keyholes in this latter layer.
摘要:
A new method is provided to create a gradated dopant concentration in the contact plug of DRAM devices whereby a high dopant concentration is present at the bottom of the plug and a low dopant concentration is present at the top of the plug. Two layers of dielectric are deposited; the upper layer serves as a layer to adjust the dopant concentration in the lower layer. This adjustment is done by Rapid Thermal anneal of both layers of dielectric. After the dopant concentration has been adjusted, the upper layer of dielectric is removed and the upper section of the contact node is formed using lightly doped poly. The high dopant concentration at the bottom of the contact plug results in low contact resistance between the plug and the underlying silicon substrate. A low dopant concentration at the top surface of the contact plug results in low oxidation of the surface of the plug.
摘要:
A process for forming a DRAM, cylindrical shaped, stacked capacitor structure, located under a bit line structure, has been developed. The process features defining a polysilicon cell plate structure, during the same photolithotgraphic and anisotropic etching procedures, used to open a bit line contact hole. The bit line contact hole is formed by first opening a top portion of the bit line contact hole, using a photoresist shape as an etch mask, and after the formation of silicon nitride spacers, on the sides of the top portion of the bit line contact hole, the bottom portion of the bit line contact hole is opened, using silicon nitride as an etch mask.
摘要:
A method of forming a deep contact by forming a dielectric layer 20 over a semiconductor structure 10. A main point is that the hard mask 30 is removed after the plug 52 is formed. A hard mask layer 30 is formed over the dielectric layer 20. A contact photoresist layer 36 is formed over the hard mask layer 30. The hard mask layer 30 is etched through the contact photoresist opening 39 to form a contact hard mask opening 41 exposing the dielectric layer 20. The dielectric layer 20 is etched using a high density plasma etch process using the contact photoresist layer 36 and the hard mask layer 30 as an etch mask forming a contact hole 40 in the dielectric layer 20. The contact photoresist layer 36 is removed. A metal layer 50 is formed filling the contact hole 40 and covering over the hard mask layer 30. The metal layer 50 is etched back forming a plug 52 filling the contact hole 40. Now, the hard mask layer 30 is removed. The removal of the hard mask 30 after the metal layer 50 deposition: (a) prevents the contact hole 40 from being contaminated from photoresist and other contamination formed during the hard mask 30 removal steps; and (b) creates a plug 52 that does not have a recess.
摘要:
A process for forming crown shaped capacitor structures, for a DRAM device, has been developed. The process features the use of a disposable insulator layer, applied prior to photolithographic and dry etching procedures, used to define the capacitor upper plate structures. The disposable insulator layer alleviates the topography effects presented by crown shaped storage node structures, relaxing the complexity of the patterning of the capacitor upper plate structures.
摘要:
A system-on-chip device comprises a first capacitor in a first region, a second capacitor in a second region, and may further comprise a third capacitor in a third region, and any additional number of capacitors in additional regions. The capacitors may be of different shapes and sizes. A region may comprise more than one capacitor. Each capacitor in a region has a top electrode, a bottom electrode, and a capacitor insulator. The top electrodes of all the capacitors are formed in a common process, while the bottom electrodes of all the capacitors are formed in a common process. The capacitor insulator may have different number of sub-layers, formed with different materials or thickness. The capacitors may be formed in an inter-layer dielectric layer or in an inter-metal dielectric layer. The regions may be a mixed signal region, an analog region, and so forth.