Cypress Semiconductor Corporation

Silicon Magnetic Systems

William W C Koutny, Jr

Anantha R Sethuraman

Krishnaswamy Ramkumar

Sagy Charel Levy

Fredrick B Jenne

Igor G Kouznetsov

Sam G Geha

Ravindra Manohar Kapre

Christopher A Seams

Yitzhak Gilboa

Jeremy L Warren

Chidambaram G Kallingal

Steven Hedayati

A semiconductor structure and method to form the same. The semiconductor structure includes a substrate having a non-volatile charge trap memory device disposed on a first region and a logic device disposed on a second region. A charge trap dielectric stack may be formed subsequent to forming wells and channels of the logic device. HF pre-cleans and SC1 cleans may be avoided to improve the quality of a blocking layer of the non-volatile charge trap memory device. The blocking layer may be thermally reoxidized or nitridized during a thermal oxidation or nitridation of a logic MOS gate insulator layer to densify the blocking layer. A multi-layered liner may be utilized to first offset a source and drain implant in a high voltage logic device and also block silicidation of the nonvolatile charge trap memory device.

Integration of non-volatile charge trap memory devices and logic CMOS devices

A method for reducing the surface roughness of a metal layer is provided. In some embodiments, the method may include polishing the metal layer to a level substantially above any layers arranged directly beneath the metal layer. In some cases, the semiconductor topography comprising the metal layer may be substantially absent of any material laterally adjacent to the metal layer during polishing. In either case, a semiconductor topography having a metal layer with a mean surface roughness less than the mean surface roughness obtained during the deposition of the metal layer may be obtained. As such, the method may include reducing the mean surface roughness of a metal layer. For example, the method may include reducing the mean surface roughness of a metal layer by at least a factor of ten.

Smooth metal semiconductor surface and method for making the same

A method is provided for eliminating a polish stop layer from a polishing process. In particular, a method is provided which may include polishing an upper layer of a semiconductor topography to form an upper surface at an elevation above an underlying layer, wherein the upper surface does not include a polish stop material. Preferably, the upper surface of the topography formed by polishing is spaced sufficiently above the underlying layer to avoid polishing the underlying layer. The entirety of the upper surface may be simultaneously etched to expose the underlying layer. In an embodiment, the underlying layer may comprise a lateral variation in polish characteristics. The method may include using fixed abrasive polishing of a dielectric layer for reducing a required thickness of an additional layer underlying the dielectric layer. Such a method may be useful when exposing an underlying layer is desirable by techniques other than polishing.

Method of making a planarized semiconductor structure

A method for reducing the surface roughness of a metal layer is provided. In some embodiments, the method may include depositing a fill layer upon a metal layer and subsequently polishing the fill layer. In some cases, the method may form a surface in which an upper surface of the fill layer is substantially level with at least one of the peaks associated with the surface roughness of the metal layer. In some cases, the surface may include portions of the metal layer and portions of the fill layer residing above the metal layer. In other cases, the method may include forming a surface in which the fill layer is arranged above the metal layer-fill layer interface. In either case, a semiconductor topography having a metal layer with a mean surface roughness less than the mean surface roughness obtained during the deposition of the metal layer may be obtained.

Semiconductor topography with a fill material arranged within a plurality of valleys associated with the surface roughness of the metal layer

The present invention advantageously provides a substantially planarized semiconductor topography and method for making the same by selectively etching a dielectric layer to form a plurality of posts surrounded by trenches. The trenches are filled with a conductive material, such as a metal, deposited to a level spaced above the upper surfaces of the dielectric layer and the posts. The surface of the conductive material is then polished to a level substantially coplanar with the upper surfaces of the dielectric layer and the posts. Advantageously, the polish rate of the conductive material above the trenches is substantially uniform. In this manner, the topological surface of the resulting interconnect level is substantially void of surface disparity.

Planarized semiconductor interconnect topography and method for polishing a metal layer to form wide interconnect structures

The present invention advantageously provides a method and apparatus for polishing a semiconductor topography by applying a liquid which is void of particles between the topography and an abrasive polishing pad surface. The semiconductor topography is rotated relative to the polishing surface to polish elevationally raised regions of the topography. The particles are fixed within the polishing surface which may comprise a polymeric material. In one embodiment, the liquid may comprise water diluted with acid. If the liquid is adjusted to have a pH between 6.0 and 7.0, the polishing process may be used to remove a silicon dioxide layer from the topography at a faster rate than a silicon nitride layer residing beneath the oxide layer. Alternately, a metal may be selectively removed from above an oxide layer if the polishing liquid has a pH between 2.0 and 5.0. In another embodiment, the liquid may be deionized water. The water does not react with the material being polished. The polishing pad is made of a non-deformable material, and thus does not conform to the elevationally disparate semiconductor topography. Therefore, elevationally raised regions of the topography are removed at a faster rate than elevationally recessed regions.

Employing an acidic liquid and an abrasive surface to polish a semiconductor topography

The present invention provides a method for cleaning particles from a semiconductor topography that has been polished using a fixed-abrasive polishing process by applying a cleaning solution including either (a) an acid and a peroxide or (b) an acid oxidant to the topography. According to an embodiment, a semiconductor topography is polished by a fixed-abrasive process in which the topography is pressed face-down on a rotating polishing pad having particles embedded in the pad while a liquid absent of particulate matter is dispensed onto the pad. The particles may include, e.g., cerium oxide, cerium dioxide, &agr;alumina, &ggr;alumina, silicon dioxide, titanium oxide, chromium oxide, or zirconium oxide. A cleaning solution comprising either (a) an acid and a peroxide, e.g., hydrogen peroxide, or (b) an acid oxidant is applied to the semiconductor topography after the polishing process is completed. Examples of acids that may be used include, but are not limited to, sulfuric acid, hydrochloric acid, hydrobromic acid, hydrofluoric acid, formic acid, acetic acid, nitric acid, perchloric acid, perbromic acid, performic acid, phosphoric acid, and peracetic acid Advantageously, the cleaning solution effectively eliminates all or at least a significant portion of the particles on the semiconductor topography.

System for cleaning a surface of a dielectric material

The present invention advantageously provides a method for using an abrasive surface and a particle-free liquid to polish a dielectric, wherein the dielectric is deposited within an isolation trench and across a polish stop surface such that a recess region of the dielectric is spaced below the polish stop surface. In an embodiment, the dielectric is an isolation oxide, and the polish stop surface belongs to an upper surface of a nitride layer formed above a silicon-based substrate. The surface of the dielectric is positioned laterally adjacent the abrasive polishing surface such that the particle-free liquid is positioned at the interface between the dielectric and the polishing surface. The particle-free liquid is preferably deionized water, and the abrasive polishing surface is preferably a polymeric matrix entrained with particles composed of, e.g., ceria. A force configured perpendicular to the backside of the substrate is applied to the polishing surface to force the dielectric surface against the polishing surface while the polishing surface is being rotated relative to the dielectric. As a result, elevationally raised regions of the dielectric are polished to the recessed region of the dielectric, planarizing the dielectric surface. The polish rate of the dielectric is substantially greater than that of the polish stop surface, and thus the polishing stop layer remains intact above the substrate. The polish rate of the elevationally raised regions of the dielectric is also greater than that of the recess region of the dielectric.

Growing community of inventors

Santa Clara, CA, United States of America

William W C Koutny, Jr