United Microelectronics Corp.

Chuck Chen

Ming-Hua Liu

Le-Tien Jung

Eddie Chen

Yo-Yi Gong

Shu-Ping Lin

Ming-Tzong Yung

A test key structure includes a substrate, a closed loop, a plurality of spacers, a plurality of first and second doping regions and a plurality of contacts. The closed loop having two conductive lines and two connection portions is located on the substrate. Each connection portion connects to one end of the conductive line and surrounds a contact region. The spacers are disposed at the edge of the closed loop to cover the substrate between the conductive lines. The first doping regions are located in the substrate outside the closed loop and the spacers. The second doping regions are located in the substrate under the spacers. The contacts are electrically connected to the first doping regions within the contact regions. Because the spacers and the conductive lines are incorporated into a test key structure, the influence of spacers upon the entire device can be more accurately determined.

Test key structure

A method of removing photoresist at the edge of waters in an integrated circuit the method comprising the following steps. A substrate having at least a MOS component region thereabove is provided. A photoresist layer is formed over the substrate. A pattern is defined on the photoresist layer by exposure and development. The photoresist layer at the edge of the substrate is removed by a chemical reagent and centrifugal effect.

Method of removing photoresist at the edge of wafers

A method of forming a self-aligned contact of a DRAM cell includes providing a substrate having a MOS transistor. The MOS transistor includes a gate and a source/drain region. A first insulating layer, a second insulating layer and a third insulating layer are formed over the surface of the substrate in succession. The third insulating layer is planarized. A contact window mask is formed above the third insulating layer. Using the contact window mask as a cover, the third insulating layer is removed using anisotropic dry etching and isotropic wet etching. Then, a portion of the second insulating layer and a portion of the first insulating layer are removed sequentially to expose the source/drain region so that a self-aligned contact is formed.

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Feng Shan, Taiwan

Chuck Chen