United Microelectronics Corp.

United Silicon Incorporated

Jen-Tsung Lin

Eddie Chen

Tsung-Hsien Han

Kuen-Chu Chen

Tang Yu

Ben Chen

Bruce Han

Da-Wen Shia

Kuo-Ping Huang

Keng-Yuan Wu

The method for avoiding polysilicon film over etch abnormal includes cleaning a semiconductor substrate. A dielectric layer is formed on the substrate. Subsequently, a first silicon source gas at a first flow rate is next performed injecting into a reaction chamber to form a first polysilicon film over the dielectric layer. Successively, a second silicon source gas at a second flow rate is performed injecting into the reaction chamber to form a second polysilicon film over the first polysilicon film, wherein the second silicon source gas having a different growth rate than the first silicon source gas. A patterned photoresist layer is then formed on the second polysilicon film. After the patterned photoresist layer is formed, a dry etching process by way of using the patterned photoresist layer as a etching mask is performed to etch through in turn the second polysilicon film and the first polysilicon film till exposing to the dielectric layer. Finally, the photoresist layer is removed.

Method for avoiding polysilicon film over etch abnormal

A method for recycling monitoring control wafers includes cleaning the wafers after performing a sheet resistance (Rs) measurement on a bare silicon monitoring control wafer of an ion implanter, and then converting the wafer into a recyclable control wafer. A recyclable control wafer for a thermal wave (TW) measurement of destruction can be obtained by forming a screen layer on the wafer, performing a TW measurement, performing ion implantation by the monitoring recipe, performing TW measurement again, performing ion drive-in to drive implanted ions into the deeper areas of the substrate, removing the screen layer, and then forming another screen layer on the wafer to put the wafer into the recycling process of a TW measurement.

Method for recycling monitoring control wafers

A method of in-line temperature monitoring. At least two control wafers and a monitor wafer are provided. A sacrificial layer is formed on each control wafer and the monitor wafer. Ions are implanted under a predetermined condition in the sacrificial layers. Thermal processes are performed on the control wafers at a higher and the lower limit of a target temperature to enable ions to move partially from the sacrificial layer to the control wafers. The sacrificial layers on the control wafers are subsequently removed. The sheet resistance of the control wafers is measured to obtain a first and the second resistance value, which respectively correspond to the first and second temperatures. A wafer and a monitor wafer are provided. A thermal process is performed on the monitor wafer and the wafer at the target temperature. The sacrificial layer of the monitor wafer is removed, and the sheet resistance of the monitor wafer is subsequently measured. When the sheet resistance of the monitor wafer is between the first and the second sheet resistance, the temperature is controlled between the first and second temperature, that is, a tolerable temperature range of the target temperature.

Method of in-line temperature monitoring

A method for determining the impurity concentration of impurity-doped polysilicon layers in semiconductor wafers is provided. Through experiments, it is found that the reflectivity of an impurity-doped polysilicon layer is nearly a regular function of the impurity concentration thereof. Accordingly, an impurity-doped polysilicon layer having an unknown impurity concentration can be determined by first measuring the reflectivity thereof by illuminating the impurity-doped polysilicon layer with light, and then using mapping transformation to find the corresponding value of impurity concentration of the impurity-doped polysilicon layer. This method can be used instead of the conventional thermal wave method that often result in having to discard the wafers due to the incapability of reliably determining the impurity concentration of the polysilicon layers formed on the semiconductor wafers.

Method of determining the impurity concentration of impurity-doped

A method for probing the error of energy or dosage in the high-energy ion implantation is disclosed herein. The error source that is from either the energy of ion implantation or the dosage of ion implantation non-normal is decided via the thermal signal value and the thickness of the remained oxidation layer after etching step. The error source can be decided by using different decision standards for phosphorous ion implantation or boron ion implantation. The method comprises the steps as follow: a semiconductor silicon wafer is provided as a test wafer, and an oxidation layer is then formed over the test wafer. A high-energy ion implantation, such as phosphorous ion implantation or boron ion implantation is performed. The oxidation layer is etched via an etching process in a fixing etching time. The thickness of the remained oxidation layer after the etching process is probed. A thermal probe is applied to probe the thermal wave signal from the ion-implant-induced damage. Afterward, the thermal wave signal value and the remained oxidation thickness of the high-energy ion implantation are compared with that of a preceding standard group. Then, the different decision standards created from the thermal wave signal value and the remained oxidation thickness for the high-energy phosphorous or boron ion implantation process are submitted. The error source that is from either the energy of ion implantation or the dosage of ion implantation in non-normal state can be decided via the different decision standards.

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Taichung, Taiwan

Jen-Tsung Lin