United Microelectronics Corp.

Cheng-Hui Chung

Yi-Chung Sheng

Chen-Bin Lin

Yei-Hsiung Lin

Chen-Chiu Hsue

Jih-Wen Chou

Bing-Chang Wu

Ching-Chun Huang

Yu-Ju Liu

Yuan-Li Tsai

James Ho

Kai-Jen Ko

Kuo-Hua Ho

Chih-Chun Huang

Belle Chia

A semiconductor wafer includes a silicon substrate, an active area positioned on the silicon substrate, and a field oxide layer positioned on the surface of the silicon substrate surrounding the active area. The present invention forms a doped area in the silicon substrate and within the active area and then deposits a dielectric layer on the surface of the semiconductor wafer. A dry etching process is performed to remove the dielectric layer. The top power of the dry etching process ranges between three hundred and five hundred watts to prevent damage to the silicon substrate near the field oxide layer and within the active area by the dry etching process, and to reduce the leakage current of the doped area. Additionally, the present invention also uses a wet etching process to remove the dielectric layer, which prevents an anisotropic physical impact on the silicon substrate near the field oxide layer to reduce the leakage current of the doped area.

Method of reducing leakage current of a semiconductor wafer

A method of manufacturing a mask ROM. A sacrificial silicon oxide layer is formed on the active region upon the substrate. Patterning the sacrificial silicon oxide layer in order to form a plurality of parallel openings, thereby exposing a portion of the active region. A polysilicon layer is formed on the openings and openings are formed thereon. An ion implantation process is performed on the polysilicon layer. Using a thermal flow process, the ions within the polysilicon layer are driven through the openings into the lower portion of the substrate, thereby forming an ion doping region. The polysilicon layer is etchbacked until the sacrificial silicon oxide layer is exposed. The sacrificial silicon oxide layer is removed.

Method of manufacturing a mask ROM bit line

A method for improving the fabrication of a transistor barrier layer that utilizes an ion bombardment treatment after the formation of the titanium nitride layer for reducing contact resistance and preventing tungsten plug stringer generation. The method comprises the step of patterning a transistor to form vias, and then depositing a titanium/titanium nitride layer over the transistor surface using a collimator sputtering method. Next, an ion bombardment treatment is carried out, and then a rapid thermal processing operation is performed. Finally, tungsten is deposited to fill the vias follow by a planarization. This invention is able to lower contact resistance because titanium in the titanium layer will not react with gaseous ammonia or nitrogen in the reacting chamber to form a high resistance titanium nitride layer during rapid thermal processing operation. In the meantime, no short-circuiting stringers leading from the tungsten plug to the titanium nitride layer below are formed because no cracks are formed in a titanium nitride layer that has been subjected to a stress reducing ion bombardment treatment.

Method of manufacturing transistor barrier layer

A method of manufacturing the metallic electrodes of a capacitor in a mixed mode semiconductor device. The method comprises the steps of providing a substrate having a conductive layer and the lower electrode of a capacitor formed thereon, and then depositing a dielectric layer over the substrate. A first opening and a second opening are then formed in the dielectric layer. The first opening exposes a portion of the conductive layer while the second opening exposes a portion of the lower electrode. Finally, a conductive plug and the upper electrode of the capacitor are formed in the respective first and second openings that are in corresponding positions above the conductive layer and lower electrode, respectively.

Method of manufacturing mixed mode semiconductor device

A method for fabricating a crack resistant inter-layer dielectric for a salicide process. The method includes forming an insulating layer on a provided substrate, forming a planarized inter-layer dielectric layer on the insulating layer, and performing a short-duration thermal treatment to increase the density of the inter-layer dielectric layer.

Method of fabricating crack resistant inter-layer dielectric for a salicide process

A method of forming metallic capacitor. The method includes forming a lower electrode for forming the capacitor and a metal conductive line over an inter-layer dielectric such that there are gaps between and on the sides of the lower electrode and the metal conductive line. Thereafter, a first oxide layer is formed that fills the gap, and then a second oxide layer is formed over the inter-layer dielectric. The second oxide layer is later patterned to form a cap oxide layer having an opening that exposes a portion of the lower electrode. Subsequently, a thin dielectric layer is formed over the lower electrode and the cap oxide layer. Finally, an upper electrode is formed over the thin dielectric layer filling the opening.

Method for forming metallic capacitor

A method of fabricating a tetra-state mask read only memory. A memory device is fabricated. Using a first photo-resist to dope the channel regions, a first coding step is performed to obtain a transistor having two different threshold voltage. Covering a gate oxide layer, and etching the first photo-resist layer to form a via, a buried bit line is formed. A poly-silicon layer is formed on the gate oxide layer. Doping the second poly-silicon layer by implanting ions to the source/drain regions, and using a second photo-resist layer, a second coding step is performed. An inverse transistor with two different threshold voltage is formed.

Method of fabricating tetra-state mask read only memory

A self-aligned silicide process for the formation of a mask ROM includes forming a self-aligned silicide layer over the bit lines and the word lines to lower the resistance of the bit lines and word lines in the mask ROM.

Silicide process for manufacturing a mask ROM

A method of fabricating flat-cell mask ROM devices having buried bit-lines that will not be subject to punch-through between neighboring bit lines as a result of heating in subsequent steps after the buried bit-lines are formed. In the method, the first step is to prepare a semiconductor substrate with a gate oxide layer formed thereon. Thereafter, a first polysilicon layer is formed over the gate oxide layer, and a plurality of trenches at predetermined positions, with these trenches extending through the gate oxide and first polysilicon layer and into the substrate to a predetermined depth. Then, trenches are filled with tungsten to form a plurality of source/drain regions. A second polysilicon layer is then formed over the first polysilicon layer, and an insulating layers is formed over each of the source/drain regions. Thereafter, a third polysilicon layer is formed over the second polysilicon layer and the insulating layers, and finally the third polysilicon layer is defined to form a gate for the integrated circuit device. Since the source/drain regions are made of tungsten metal, the spacing distance therebetween will not be changed when subjected to high-temperature conditions during subsequent process steps. The punch-through effect can thus be avoided.

Method of fabricating flat-cell mask read-only memory (ROM) devices

A method of fabricating a high density flat mask read only memory. At first a plurality of trenches are formed in a surface of a silicon substrate at predetermined desired source-drain electrodes areas. A dielectric layer is formed on at least the surface of the trenches. A first polysilicon layer is formed over the dielectric layer and then portions of the first polysilicon layer are removed to leave a portion thereof on the bottom of each trench. Using the first polysilicon layer as an etch stop layer, the dielectric layer is etched. A second polysilicon layer then is formed on the surface of the silicon substrate, the first polysilicon layer and the dielectric layer, and then the the second polysilicon layer is etched back to the substrate surface to form the source-drain electrode areas, that is, the bit lines. On the surface of the bit lines and the silicon substrate, a gate oxide layer and a third polysilicon layer are formed sequentially. Finally, the gate oxide layer and the third polysilicon layer are defined to form gate electrodes, that is, word lines for the memory.

Method of fabricating high density flat cell mask ROM

A method of fabricating memory cells with buried bit lines. In this method, a pad oxide layer is formed on a first conductivity-type silicon substrate. A photoresist layer is formed on the pad oxide layer while exposing predetermined areas of channels. A thick oxide layer is deposited by liquid phase deposition (LPD). The photoresist layer is removed. Second conductivity-type impurities are implanted to form source-drain electrodes using the thick oxide layer as a mask. The thick oxide layer and the pad oxide layer are removed to form bit lines and then word lines are formed crossing the bit lines, whereby the structure with buried bit lines and an array of memory cells is completed.

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Hsinchu Hsien, Taiwan

Cheng-Hui Chung