United Microelectronics Corp.

Other

Jason Jyh-shyang Jenq

Sun-Chieh Chien

Der-Yuan Wu

Chia-Wen Liang

Chuan-Fu Wang

Benjamin Szu-Min Lin

Kun-Cho Chen

Gary Y Hong

Tung-Po Chen

King-Lung Wu

C C Hsue

An electrode for a DRAM charge storage capacitor is provided with a textured surface using a wet etching process that has far greater process latitude and a lower cost than conventional processes for forming hemispherical grained silicon. A base capacitor electrode is provided for a DRAM cell preferably having a conventional polysilicon surface on which the textured surface will be formed. A layer of polycrystalline material having a composition different from the polysilicon surface is provided over the polysilicon surface. The layer of polycrystalline material is subjected to a wet etching process which preferentially etches along the grain boundaries of the layer of polycrystalline material. This wet etching process removes portions of the layer of polycrystalline material from over the polysilicon surface. The remaining portions of the layer of polycrystalline material are then used as a mask for etching the surface of the polysilicon, introducing a texture to the surface of the polysilicon layer. The surface of the polysilicon layer is then cleaned and a capacitor dielectric and upper capacitor electrode are provided over the textured polysilicon surface.

Method to increase DRAM cell capacitance

A method of fabricating a capacitor of a dynamic random access memory is provided. A substrate is first provided, wherein a first dielectric layer is formed on the substrate, and a via is formed through the first dielectric layer to expose one of source/drain regions. A conductive material is formed on the first dielectric layer so that the conductive material is filled in the via to contact with the one of the source/drain regions. The conductive material is patterned to form a first conductive layer. A hemispherical polysilicon grain layer is formed at least on the first conductive layer. The hemispherical polysilicon grain layer is etched back so that the first conductive layer and the hemispherical polysilicon grain layer together form a lower electrode. A second dielectric layer is formed on the lower electrode. A second conductive layer is formed on the second dielectric layer to be an upper electrode.

Method of fabricating a capacitor of dynamic random access memory

A method of making contact openings for memory cell units of DRAM IC devices is disclosed. The contact opening is used to connect the cell transistor source/drain terminal to the storage capacitor electrode located substantially above. The method includes the step of first patterning the initial opening in a shielding layer for the contact opening. The diameter of the initial opening is then reduced by the formation of sidewall spacers in initial opening. The initial opening in the shielding layer is then used to implement the etching for the formation of the contact opening. Due to reduced size of the contact opening, short-circuiting situations arising between the via formed in the contact opening and the bit lines next to the via as a result of misalignment in the process of fabrication can be reduced, thereby improving the device fabrication yield rates.

Method of fabricating contact openings for dynamic random-access memory

A wafer structure on an IC chip allows the bonding pads on the IC chip to be firmly secured to the IC chip, thereby preventing detachment of the bonding pads during assembly of the IC package. The wafer structure comprises a substrate on which at least a pad area is defined. The pad area is formed with a first insulating layer, a gate on the first insulating layer, a second insulating layer on the gate, and a third insulating layer on the second insulating layer. The second insulating layer has a plurality of lower openings formed therethrough and the third insulating layer has a plurality of upper openings formed therethrough, each upper opening corresponding to one of the lower openings. The lower openings are wider than the upper openings. Plugs are formed in the lower and upper openings and are bonded to a metallization layer which serves as a bonding pad for the IC chip. The wider lower part of the plugs allows them to be rigidly affixed within the openings, thus allowing the overlaying bonding pad to be firmly secured to the IC chip. Therefore, during assembly of the IC chip, the bonding pad is not readily detached from the IC chip, thus increasing the assembly yield of good IC packages.

Wafer structure for securing bonding pads on integrated circuit chips

A method of manufacturing a DRAM capacitor comprises the steps of providing a substrate having a word line, a source/drain region, a bit line and a first insulator layer. A hard mask layer and a second insulator layer are formed on the first insulator layer in sequence. Next, an opening is formed to expose a portion of the first insulator layer by patterning the second insulator layer and the hard mask layer. Thereafter, a spacer is formed on the side wall of the opening and a node contact hole is formed to expose a portion of the source/drain region in the first insulator layer. The second insulator layer is stripped to expose the hard mask layer and a conductive layer is formed over the hard mask layer and fills the node contact hole. A bottom electrode is formed by patterning the conductive layer and a dielectric layer and another conductive layer are formed over the bottom electrode in sequence.

Method of manufacturing a DRAM capacitor

A method for manufacturing a DRAM capacitor is provided to form a lower electrode with a cylindrical profile by using a first stage and a second stage. The stages provide different etching rates in various situations. The invention uses the stages to allow the part of the second polysilicon layer between the capacitors to be completely etched and prevent the other part of the second polysilicon layer serving as a lower electrode from over-etching. The invention provides an easier process of forming a cylindrical capacitor with a larger surface.

Method for manufacturing DRAM capacitor

The DRAM cell is formed by covering the cell's transfer FET with a conformal insulating layer. A self aligned contact etch removes a portion of the conformal insulating layer from above a first source/drain region of the FET and then a first polysilicon layer is deposited over the device. Etching defines a polysilicon pad from the first polysilicon layer with edges of the polysilicon pad disposed over the gate electrode and an adjacent wiring line. A thick, planarized second insulating layer is provided over the device, filling the volume defined by the locally cupped surface of the polysilicon pad. Etching is performed to remove a portion of the planarized insulating layer using the pad polysilicon layer as an etch stop for the process. A second, thick polysilicon layer is next provided to fill the cavity and the layer is patterned to laterally define the lower capacitor electrode. Hemispherical grained silicon (HSG-Si) is deposited on the surface of the patterned polysilicon layer and an etch back process is used to transfer the topology of the HSG-Si layer to the underlying polysilicon. Further processing provides a capacitor dielectric and an upper electrode.

Method of fabricating a Fin/HSG DRAM cell capacitor

Bonding pad structures may be fabricated by forming a layered structure including a first conducting layer and first and second insulating layers on top of a substrate. Openings are etched through the first and second insulating layers, with the openings being wider in the first insulating layer than in the second insulating layer. The etching process may be carried out in two steps, with the second step preferentially isotropically etching the first insulating layer so that the openings are wider in the first insulating layer than in the second insulating layer and a portion of the second insulating layer overhangs the opening above the first insulating layer. Metal is then deposited within the openings and on top of the second insulating layer. An interlocking structure is formed with the conducting material extending underneath of the overhang portions of the second insulating layer. A passivation layer may be formed over the conducting material. The conducting material may include a barrier layer, a plug, and a top bond pad layer.

Method and structure for preventing bonding pad peel back

A method of fabricating a bit line comprises first that a semiconductor substrate is provided. The substrate comprises source/drain regions and a semiconductor structure. Over the substrate, an oxide layer conformal to the semiconductor substrate and a BPSG layer are formed. A contact window is formed and exposes the source/drain regions in the substrate. A polysilicon layer is formed within the contact window and connects the source/drain regions. A titanium silicide (TiSi.sub.2) is formed and covers the polysilicon layer. A titanium nitride layer is formed and covers the titanium silicide layer. One of the characteristics of the invention is that a titanium silicide layer, a titanium nitride layer, and a polysilicon layer replaces the conventional tungsten silicide and the polysilicon layer to form a bit line. Therefore, the contact resistance of the bit line is reduced effectively. In addition, the titanium nitride layer can be used as a bottom anti-reflection layer to avoid the necking phenomenon while coating photoresist. Moreover, the titanium nitride layer also prevents the formation of cracking during the subsequent rapid thermal process.

Method of fabricating bit line

A method for forming dual damascene metallic structure that utilizes the formation of a protective photoresist layer at the bottom of a vertical window to prevent damages to a device region in the substrate when subsequent etching operation is carried out to form a horizontal trench pattern. The protective photoresist layer at the bottom of the vertical window is formed by irradiating the photoresist layer with a dose of radiation having energy level insufficient to chemically dissociate the photoactive molecules of the photoresist layer near the bottom of the vertical window.

Method for forming dual damascene structure

A method for forming a DRAM capacitor that utilizes silicon nitride spacers on two occasions to perform self-aligned contact window etching operations. Furthermore, on the second etching operation, one less photomask is required for the etching of the second via. In addition, a silicon nitride layer over the first polysilicon layer has a smaller thickness than the usual oxide layer in a conventional method of manufacture. Consequently, a shallower contact step height for the capacitor, which is beneficial to the production of miniaturized devices, is obtained. Finally, the tri-fork shaped capacitor structure further increases the surface area of the capacitor so that the capacitance of the DRAM capacitor is increased.

A method for fabricating DRAM capacitor which includes forming a transistor having a source/drain regions and a gate electrode above a silicon substrate; then, forming sequentially a stack of layers including a first insulating layer, a second insulating layer, a third insulating layer and a hard mask layer over the transistor; subsequently, patterning and etching the hard mask layer. Thereafter, an oxide layer is formed over the hard mask layer, and then portions of the layers are etched to form a capacitor region over the oxide layer and a contact opening exposing a portion of the source/drain region. In the subsequent step, a conducting layer is formed over the oxide layer, the hard mask layer, the sidewalls of the contact opening and the exposed portion of the source/drain region. Next, a polishing method is used to remove the conducting layer above the oxide layer, and then the oxide layer is removed to form a lower electrode. A dielectric layer is then formed over the lower electrode, and finally an upper electrode layer is formed over the dielectric layer.

Method of fabricating DRAM capacitor

A process for fabricating bitlines for DRAM devices having improved bitline electrical contact is disclosed. Good electrical connection for the bitline in its contact opening is secured by forming a contact interface utilizing titanium silicide. The process includes first forming contact openings revealing the source/drain regions of the transistor of the cell units followed by the formation of a polysilicon layer filling into the openings and contacting the revealed surface of the transistor source/drain regions. A tungsten silicide layer then covers the polysilicon layer, with a titanium layer further covering the tungsten silicide layer, and the polysilicon layer in the contact opening exposed out of coverage by the tungsten silicide layer due to insufficient step coverage of the tungsten silicide layer in the openings. A titanium nitride layer then covers the titanium layer, with a titanium silicide layer interfacing between the polysilicon layer and the tungsten silicide filled inside the openings.

Process for fabricating bitlines

A DRAM is formed by providing a transfer FET, providing an elevated structure over and adjacent to the transfer FET and then forming a cavity above one of the source/drain regions of the transfer FET. The cavity is filled with a conductor to define in part a lower electrode of a charge storage capacitor. Portions of the cavity are then removed to expose additional charge storage surfaces for the lower electrode of the charge storage capacitor. The elevated structure includes a thick, planarized insulating layer provided over the transfer FET. A cavity is formed by providing an etching mask over the thick, planarized insulating layer with an opening positioned over the first source/drain. Etching is performed to remove a portion of the second insulating layer. A thick polysilicon layer is provided to fill the cavity and then the second, thick polysilicon layer is patterned to laterally define the lower capacitor electrode, preferably leaving portions of the second polysilicon layer extending above the stepped opening and onto surrounding portions of the second insulating layer. The second insulating layer is then removed to expose additional surfaces of the lower capacitor electrode for charge storage. Processing continues to provide a capacitor dielectric layer, an upper capacitor electrode and a bit line contact to complete the DRAM.

Method of fabricating a fin/cavity capacitor structure for DRAM cell

A process of fabricating the storage capacitor of a DRAM memory IC device having increased electrode surface area is disclosed. The hemispherical-grain silicon layer used to effect the area increase does not suffer stripping-off during the process of removal of its native oxide. The prevention of the stripping-off is achieved by the employment of a amorphous silicon layer underlying the hemispherical-grain silicon layer. The amorphous silicon layer improves the adhesiveness of the hemispherical-grain silicon layer, thereby preventing its stripping-off.

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Pingtung, Taiwan

Jason Jyh-shyang Jenq