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Zigzag RMG Gate via EUV Direct Patterning to Enable Work Function Patterning for Extremely Scaled High Performance CMOS

IP.com Disclosure Number: IPCOM000248199D
Publication Date: 2016-Nov-08
Document File: 5 page(s) / 107K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to have the extended gate (i.e., larger poly contact(PC) critical dimension(CD)) outside the active Rx and the normal gate (i.e., normal PC CD) inside the active Rx, which forms a zigzag gate through extreme ultraviolet (EUV) direct patterning (i.e., print and reactive ion etch (RIE)). This allows the replacement metal gate (RMG) to enable the dual work function metal patterning and lower the gate resistance.

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Page 01 of 5

Zigzag RMG Gate via EUV Direct Patterning to Enable Work Function Patterning for Extremely Scaled High Performance CMOS

PC CD is decreasing in size, which presents a challenge in allowing the dual WF metal patterning, especially when the gate length is scaled to sub-15nm. For example, when the gate CD is small, the organic planarization layer(OPL) cannot be deposited into the trench to prevent the lateral over etch when performing dual work function (WF) patterning (Figure 1).

Figure 1: Example of the problem (Here HK is high k dielectric)

Based on gate resistance calculation, a lower resistivity material at the end of the gate can help reduce gate resistance.

The novel solution is to have the extended gate (i.e., larger PC CD) outside the active Rx and the normal gate (i.e., normal PC CD) inside the active Rx, which forms a zigzag gate through extreme ultraviolet (EUV) direct patterning (i.e., print and reactive ion etch (RIE)). This allows the replacement metal gate (RMG) to enable the dual work function metal patterning and lower the gate resistance (Figure 2).

Figure 2: Our invention proposal

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Page 02 of 5

This solution enables dual WF patterning. Without such zigzag gate, the OPL cannot be deposited in the gate trench for 11nm Lg after the first work function metal deposition, even after hk recess. However, if the zigzag gate is formed, the larger gate in the shared portion allows the OPL deposition and then performs the patterning.

Figure 3: The topdown v...