United Microelectronics Corp.

Chien-Hua Tsai

Chih-Cheng Liu

Chin-Hui Lee

Kun-Chi Lin

Jui-Tsen Huang

Tsu-An Lin

Alex Hou

Horng-Non Chern

A semiconductor wafer comprises a silicon substrate, and a dielectric layer. A gate is formed on the dielectric layer. A first silicon oxide layer is uniformly formed on the semiconductor wafer. A first ion implantation process is performed to form two doped areas on the silicon substrate that are used as two lightly doped drains of a MOS transistor. A second silicon oxide layer is formed on the semiconductor wafer. A sacrificial layer is formed on the second silicon oxide layer. A first etching process is performed to remove the sacrificial layer on top of the gate, causing the gate to protrude from the remaining sacrificial layer for a predetermined height. A second etching process is performed to remove the first and second silicon oxide layers on the protruding portion of the gate. After removing the sacrificial layer completely, a silicon nitride layer is uniformly formed on the semiconductor wafer. A third etching process is performed to vertically remove the silicon nitride layer on top of the gate, thereby forming a spacer. Finally, a second ion implantation process is performed to form two doped areas on the silicon substrate, which are used as source and drain of the MOS transistor.

Method of a metal oxide semiconductor on a semiconductor wafer

The present invention provides a method of forming a contact hole in a semiconductor wafer. The semiconductor wafer comprises a silicon substrate, a silicon--oxygen layer positioned on the silicon substrate, and a photoresist layer positioned on the silicon--oxygen layer. An anisotropic dry-etching process is performed to vertically remove the silicon--oxygen layer below the opening to a predetermined depth to form the contact hole which contains a polymer layer on its surface. A soft-etching process is performed to remove the polymer layer in the contact hole. The dry-etching process and soft-etching process are performed alternatively to vertically remove the silicon--oxygen layer under the contact hole until the surface of the silicon substrate can be reached through the contact hole.

Method of forming a contact hole in a semiconductor wafer

A method for forming a different width of gate spacer is disclosed. The method includes firstly forming a gate oxide layer on a semiconductor substrate. A polysilicon layer, a conductive layer, a first dielectric layer are formed in order on the gate oxide layer. The first dielectric layer, the conductive layer, the polysilicon layer, and the gate oxide layer are further etched using them as the interior gate and the peripheral gate. Next, second dielectric layer, third dielectric layer, and fourth dielectric layer are formed over the interior gate and the peripheral gate, and a first photoresist layer abuts the surface of the fourth dielectric layer of the interior circuit. Moreover, etching the fourth dielectric layer of peripheral gate to form a second spacer of peripheral gate, and etching the third dielectric layer of the peripheral gate are undertaken to form a first spacer of the peripheral gate. Removing the first photoresist layer and the fourth dielectric layer of the interior circuit, a fifth dielectric layer is formed on the third dielectric layer of the interior circuit. The fourth dielectric layer and the top surface of the second dielectric layer of the peripheral circuit are removed. The fifth dielectric layer is formed on the first dielectric layer and the third peripheral of the peripheral circuit, and then the second photoresist layer on the fifth dielectric layer, wherein the third photoresist layer is patterned as a bit-line contact via of the interior circuit and the bit-line contact vias of the peripheral circuit. Finally, anisotropically etching the third photoresist layer and the fifth dielectric layer, a bit-line to the substrate contact via and a bit-line to the gate contact via are formed inside the fifth dielectric layer.

Method for forming gate spacers with different widths

Growing community of inventors

Tai-Chung, Taiwan

Chien-Hua Tsai