Taiwan Semiconductor Manufacturing Comp. Ltd.

Chi-Ju Lee

Harry-Hak-Lay Chuang

Bao-Ru Young

Ming Zhu

Lee-Wee Teo

Sheng-Chen Chung

Jin-Aun Ng

Yu-Ying Hsu

Sin-Hua Wu

Kai-Shyang You

A method of preventing contact metal from protruding into neighboring gate devices to affect work functions of the neighboring gate devices is provided includes forming a gate structure. Forming the gate structure includes forming a work function layer, and forming a gate metal layer having a void, wherein the work function layer surrounds the gate metal layer. The method further includes forming a contact plug having a contact metal directly on the gate metal layer of the first gate stack, wherein the contact metal protrudes into the void, and the work function layer prevents the contact metal from protruding into a second gate stack.

Methods to stop contact metal from extruding into replacement gates

The methods and structures described are used to prevent protrusion of contact metal (such as W) horizontally into gate stacks of neighboring devices to affect the work functions of these neighboring devices. The metal gate under contact plugs that are adjacent to devices and share the (or are connected to) metal gate is defined and lined with a work function layer that has good step coverage to prevent contact metal from extruding into gate stacks of neighboring devices. Only modification to the mask layout for the photomask(s) used for removing dummy polysilicon is involved. No additional lithographical operation or mask is needed. Therefore, no modification to the manufacturing processes or additional substrate processing steps (or operations) is involved or required. The benefits of using the methods and structures described above may include increased device yield and performance.

Structures and methods to stop contact metal from extruding into replacement gates

The embodiments of methods described in this disclosure for trimming back nitride spacers for replacement gates allows the hard mask layers (or hard mask) to protect the polysilicon above the high-K dielectric during trim back process. The process sequence also allows determining the trim-back amount based on the process uniformity (or control) of nitride deposition and nitride etchback (or trimming) processes. Nitride spacer trim-back process integration is critical to avoid creating undesirable consequences, such as silicided polyisicon on top of high-K dielectric described above. The integrated process also allows widening the space between the gate structures to allow formation of silicide with good quality and allow contact plugs to have sufficient contact with the silicide regions. The silicide with good quality and good contact between the contact plugs and the silicide regions increase the yield of contact and allows the contact resistance to be in acceptable and workable ranges.

Method for main spacer trim-back

Main spacer trim-back method for replacement gate process

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Guiren, Taiwan

Chi-Ju Lee