News Column

Patent Issued for Semiconductor Device Having Metal Gate and Manufacturing Method

July 16, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- United Microelectronics Corp. (Science-Based Industrial Park, Hsin-Chu, TW) has been issued patent number 8765591, according to news reporting originating out of Alexandria, Virginia, by VerticalNews editors.

The patent's inventors are Fu, Ssu-I (Kaohsiung, TW); Tseng, I-Ming (Kaohsiung, TW); Liou, En-Chiuan (Tainan, TW); Chen, Cheng-Guo (Changhua County, TW).

This patent was filed on September 11, 2013 and was published online on July 1, 2014.

From the background information supplied by the inventors, news correspondents obtained the following quote: "The invention relates to a semiconductor device having a metal gate and manufacturing method thereof, and more particularly, to a semiconductor device having a metal gate and manufacturing method applied with a gate last process.

"With a trend toward scaling down the size of the semiconductor device, work function metals are used to replace the conventional polysilicon gate to be the control electrode that competent to the high-K gate dielectric layer. The conventional dual metal gate methods are categorized into the gate first process and the gate last process. Among the two main approaches, the gate last process is able to avoid processes of high thermal budget and to provide wider material choices for the high-K gate dielectric layer and the metal gate, and thus gradually replaces the gate first process.

"In a conventional gate last process, a dummy gate or a replacement gate is formed on a substrate and followed by steps of forming a conventional metal-oxide semiconductor (MOS) transistor device and forming an inter-layer dielectric (ILD) layer. Subsequently, the dummy/replacement gate is removed to form a gate trench. And the gate trench is filled with metal layers required for different conductivity types. As the line width of the transistor device keeps shrinking, the aspect ratio of the gate trench becomes more and more critical when filling the gate trench with the metal layers. Briefly speaking, when the line width of the transistor device is reduced, the opening width of the gate trench is consequently reduced, and thus it is difficult to fill the gate trench with the metals, it even causes a seam left in the metal gate after forming the metal layers in the gate trench. Eventually, the electrical performance of the transistor device having the metal gate is deteriorated.

"It is found that the gate last process is able to avoid processes of high thermal budget and to provide wider material choices for the high-K gate dielectric layer and the metal gate. However, the gate last process still faces integrity requirements for the complicated processes and reliability requirement for the gate trench filling."

Supplementing the background information on this patent, VerticalNews reporters also obtained the inventors' summary information for this patent: "According to a first aspect of the present invention, there is provided a method of manufacturing a semiconductor device having metal gate. The method includes providing a substrate having at least a dummy gate, a sacrificial layer covering sidewalls of the dummy gate and a dielectric layer exposing a top of the dummy gate formed thereon, performing a first etching process to remove a portion of the sacrificial layer surrounding the top of the dummy gate to form at least a first recess, and performing a second etching process to remove the dummy gate to form a second recess, the first recess and the second recess constructing a T-shaped gate trench.

"According to a second aspect of the present invention, there is provided a semiconductor device having metal gate. The semiconductor device includes a substrate, a high-K gate dielectric layer, a T-shaped metal gate, a source/drain positioned in the substrate at two sides of the T-shaped metal gate, and a sacrificial layer formed at two sides of the T-shaped metal gate. The T-shaped metal gate includes a head portion and a body portion formed under the head portion for supporting the head portion. The sacrificial layer at least is formed under the head portion of the T-shaped metal gate.

"According to the semiconductor device having a metal gate and the method of manufacturing a semiconductor device having metal gate provided by the present invention, the T-shaped gate trench constructed by the first recess and the second recess is obtained by performing two etching processes. According to the present invention, the T-shaped gate trench includes a larger opening width, thus the metal layers are easily formed in the trench gate. Consequently, the semiconductor device having metal gate provided by the present invention has the advantage of superior gap-filling result and improved reliability.

"These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings."

For the URL and additional information on this patent, see: Fu, Ssu-I; Tseng, I-Ming; Liou, En-Chiuan; Chen, Cheng-Guo. Semiconductor Device Having Metal Gate and Manufacturing Method. U.S. Patent Number 8765591, filed September 11, 2013, and published online on July 1, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8765591.PN.&OS=PN/8765591RS=PN/8765591

Keywords for this news article include: Semiconductor, United Microelectronics Corp.

Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC


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Source: Electronics Newsweekly


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