Lga substrate and method of making same

Abstract

A transistor comprises a gate ( 110 ) comprising a gate electrode ( 111 ) and a gate dielectric ( 112 ), an electrically insulating cap ( 120, 720 ) over the gate, and a source/drain contact ( 130 ) adjacent to the gate. The electrically insulating cap prevents electrical contact between the gate and the source/drain contact. In one embodiment, the electrically insulating cap is formed in a trench ( 160, 660 ) that is self-aligned to the gate and that is created by the removal of a sacrificial cap using an aqueous solution comprising a carboxylic acid and a corrosion inhibitor.

1 . A transistor comprising:
 a gate comprising a gate electrode and a gate dielectric;   an electrically insulating cap over the gate; and   a source/drain contact adjacent to the gate,   wherein:
 the electrically insulating cap prevents electrical contact between the gate and the source/drain contact. 
   
     
     
         2 . The transistor of  claim 1  further comprising:
 an electrically insulating layer over the gate; and   a trench in the electrically insulating layer and aligned to the gate,   wherein:
 the electrically insulating cap is in the trench. 
   
     
     
         3 . The transistor of  claim 2  wherein:
 the gate electrode is a metal gate electrode;   the gate dielectric is a high-k dielectric material; and   the gate further comprises a workfunction metal between the gate electrode and the gate dielectric.   
     
     
         4 . The transistor of  claim 3  wherein:
 the metal gate electrode comprises copper.   
     
     
         5 . The transistor of  claim 1  further comprising:
 a sacrificial capping layer temporarily located over the gate,   wherein:
 the sacrificial capping layer is removed prior to a formation of the electrically insulating cap; 
 the sacrificial capping layer comprises a metal taken from the group consisting of cobalt and nickel; and 
 the gate electrode comprises copper.