The Defect Reduction of Via Opens by the Integration of Inter-Metal-Dielectric Film, Metal Hard Mask, and All-in-One Etch Processes

Abstract

This research aims at the pattern failure defects by the backend all-in-one (AIO) etching process during a recent technology development in a 12-inch FAB. The AIO etch directly defines the shape of both trench and via, however, those previous process steps involving the deposition of inter-layer-dielectric film, metal hard mask and the wet clean would contribute to the AIO etch performance and even cause pattern defects. The investigation elucidates the count of pattern failure defects strong correlates with the life time of ST250 which was used to remove polymer post metal hard etch process. The experiments shows that to extend ST250 rise time and add a scrubber process step can achieve a comparable defect performance with the old acid which run time > 50hrs. Eventually, the additional scrubber process was added to reduce defect counts and gained end-of-the-line 4% yield.

High-Performance Metal Hard Mask Process Using Fiber-Textured TiN Film for Cu Interconnects

“…[12][13][14][15][16][17][18][19][20][21][22][23][24] As a hard mask in the MHM process, Titanium nitride (TiN) has been investigated. [20][21][22][23][24][25][26][27][28][29][30][31] This is because the alignment pattern for photolithography can be easily recognized through TiN film compared to other metal films such as Tantalum nitride (TaN) film.…”

“…To suppress the damage of interlayer dielectric by the ashing process during the removal of the trench resist, the metal hard mask (MHM) process has been studied instead of the conventional resist mask process. [12][13][14][15][16][17][18][19][20][21][22][23][24] As a hard mask in the MHM process, Titanium nitride (TiN) has been investigated. [20][21][22][23][24][25][26][27][28][29][30][31] This is because the alignment pattern for photolithography can be easily recognized through TiN film compared to other metal films such as Tantalum nitride (TaN) film.…”

High-Performance Extremely Low-k Film Integration Technology with Metal Hard Mask Process for Cu Interconnects

“…Hence, the degradation of reliability performance such as time dependent dielectric breakdown (TDDB) lifetime between Cu lines with vias is one of the most critical issues. Therefore, the self-aligned via process has been reported, [16][17][18][19] and the metal hard mask (MHM) process has been studied [20][21][22][23][24][25][26][27][28][29][30][31][32] instead of the conventional resist mask process to suppress the damage of interlayer dielectrics by the ashing process with oxygen (O 2 ) plasma. [33][34][35] We have studied the MHM process using the low stress TiN mask which had a fiber-textured structure for the perfect Cu filling and it has been demonstrated to be high performance.…”