Abstract:
A fabrication method for a read only memory provides a substrate having a memory cell region and a periphery circuit region. A memory cell region has a memory cell array and the periphery circuit region has transistors. A precise layer having a plurality of first openings is formed in the memory cell region. The first openings are above the channel region of each memory cell in the memory cell array and the critical dimension of the first openings is identical. A mask layer having second openings and third openings is formed on the substrate. The second openings locate over a pre-coding memory cell region, and the third openings locate over the transistor gates. An ion implantation is performed to code the memory cell in the pre-coding memory cell region and to adjust the threshold voltage of the transistor, using the precise layer and the mask layer as a mask.
Abstract:
A method and system for cleaning lens used in an immersion lithography system is disclosed. After positioning a wafer in the immersion lithography system, a light exposing operation is performed on the wafer using an objective lens immersed in a first fluid containing surfactant, wherein the surfactant reduces a likelihood for having floating defects adhere to the wafer and the objective lens.
Abstract:
A method of fabricating a phase shift mask (PSM) is described. A patterned photoresist layer is formed on an opaque layer over a transparent plate. A thin mask layer is formed on the sidewalls of the patterned photoresist layer. The exposed opaque layer and transparent plate thereunder are then removed while using the patterned photoresist layer and mask layer as a mask. A phase shift opening is formed in the transparent plate, and thereby a phase shift layer is formed at the place where the phase shift opening is located. The patterned photoresist layer and the opaque layer thereunder are then removed to expose the transparent plate. The opaque layer under the mask layer can precisely self-align the phase shift layer to prevent alignment deviation caused by multiple lithography processes. The precision of the phase shift mask can be increased, and mask manufacture cost can be lowered.
Abstract:
A method of forming a feature pattern in a photosensitive layer includes forming the photosensitive layer on a substrate, providing a first mask having a first opaque area thereon, and performing a first exposure process with a first dose to form a first unexposed image in the photosensitive layer. The method further includes performing a second exposure process with a second dose to expose sidewalls of the first unexposed image so that the sidewalls of the first unexposed image receive at least a portion of the second dose thus forming a second unexposed image in the photosensitive layer, and developing the photosensitive layer with a developing process to form the feature pattern and to create features having smaller widths than those which would result in developing the photosensitive layer of the first unexposed image.
Abstract:
A method of forming holes in a layer through a cross-shape image exposure. The method includes removing a section from each corner of the rectangular patterns on a photomask to form cross-shape patterns so that circular or elliptical contact holes are formed on a photoresist layer after photo-exposure and development. Optical image contrast between contacts is increased by the cross-shape patterns on the photomask.
Abstract:
A stringer block is formed on the interface between a HDP silicon oxide layer and a silicon substrate. During an etching process for defining the profile of a floating gate, the stringer block functions to expose a bottom corner stringer. Following that, a polysilicon etching process effectively removes the bottom corner stringer. As a result, a stringerless flash memory cell is formed to prevent leakage currents, resulting from the bottom corner stringer, and improve both the reliability and data retention ability of the device.
Abstract:
A method of code programming a mask read only memory (ROM) is disclosed. According to the method, a first photoresist layer is formed over word lines and a gate oxide layer of a substrate already having implanted bit lines. The first photoresist layer is patterned to develop pre-code openings over all of the memory cells, which correspond to intersecting word and bit lines. The first photoresist layer is then hardened using either a treatment implant or a treatment plasma. Subsequently, a second photoresist layer is formed over the first photoresist layer and patterned to develop real-code openings over memory cells which are actually to be coded with a logic “0” value. Each memory cell to be coded is then implanted with implants passing through the pre-code openings and the real code openings and into the memory cell.
Abstract:
A method of wafer reclaim, at least includes: provide a wafer; perform a first semiconductor process to let both film layer and numerous particles are formed on the wafer; perform chemical mechanical polishing process to let part of film layer is removed and scales of part of particles are decreased; perform wet etching process to let both residual film layer and residual particles are further removed; perform cleaning process to let surface of wafer is cleaned; and perform second semiconductor process to let a semiconductor structure is formed on wafer. Furthermore, concepts of the invention that both film layer and particles are thoroughly removed by both chemical mechanical polishing process and wet etching process can be applied as a method for cleaning wafer and a method for planarizing wafer.
Abstract:
A method that, using the surface-reaction mechanism of polysilicon in the chemical vapor deposition (CVD) process, starts in depositing a conformal first polysilicon layer on a uneven surface of a semiconductor wafer. The first polysilicon layer is then oxidized to a conformal first silicon oxide thin film. By repeating the previous two steps, a second polysilicon layer is formed on the surface of the first silicon oxide thin film and then oxidized to a second silicon oxide thin film with the required thickness. The conformal silicon oxide thin film formed by the method can be applied in structures of various devices in refined processes.
Abstract:
A method for forming a protection device with slope laterals is provided. Firstly, providing a semiconductor substrate having a plurality of alternative first sacrificial layers and second sacrificial layers formed thereon. A first etching step is performed to remove one portion of each of the first sacrificial layers and thereby expose one portion of each lateral of each of the second sacrificial layers. Subsequently, performing a second etching step to remove one portion of the lateral of the second sacrificial layer. Then, repeatedly and alternately performing the first etching step and the second etching step until completely removing the first sacrificial layers and then obtaining a plurality of protection devices formed of the second sacrificial layers each of which having slope laterals.