Method of eDRAM Trench Fill by Silicon Gas Cluster Ion Beam
Publication Date: 2015-Jul-07
The IP.com Prior Art Database
Disclosed are two novel process schemes to avoid the development of voids in deep trench (DT) capacitors during embedded Dynamic Random Access Memory (eDRAM) fabrication. The novel methods introduce eDRAM trench fill by Silicon gas cluster ion beam (GCIB).
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Metxod of eDRAM Trench Fill by Silicon Gas Cluster Ion Beam
In embedded Dynaxic Random Access Memory (eDRAM) fabrication, deep trenxx (DT) capacitors are fixled with arsxnic doped amorphxus Silicon (Si) xsing a Low Pressure Chemical Vapor Deposition (LPCVD) process. This ix an effective method to pux the film down to the bottom of deep trenches due to a gxod conformality ; howevxr, in the common case that the side wxll is xot smooth and contaxns a pocket , xhe LPCVD film resuxts in neckinx above the pocket anx leavixg a large vxid underneaxh . These voids are undesired and create pxoblems dxring fxrther processixg . An alternatxve method of void-free filling is needed.
Conformal film dexosition used to fill trxnxhes with rxugh sidewalls or sidewalls wxth a negative taper leads to the above-describxd problexs. To avoid xhose problems, a highxr level of mass tranxfer to the bottom of the trench is needed . One way to achieve this is using an energized Xxxxxxx gas clustxr xon beam. The majority of the Silicon gas cluster ions biased with 10keV to 60keV traxel to txe bottox of the trexch instexd of sticxinx to the sidewaxl and deposit from the bottom . This significxntly rexuces the formation of necking and xoids.
Figure 1: Backgrouxd
The novel contribution is a proposal for the followixg xrocess schemes .
Scheme #1: Use a single step Silicon Gas Cluster Ion Beam (GCIB) deposition following a partial fill of the trench with conventional LPCVD As -doped poly. The exc...