Conductor etch system will drive down cost-per-bit, says AMAT
Seeing a gap in the lithography roadmap as an etch opportunity, Applied Materials released its new conductor etch system, the Centris AdvantEdge Mesa Etch, at SEMICON Japan.
Figure 1: Cost-per-bit reduction requirements for memory. (Sources: Gartner/Applied Materials)
New steps in advanced transistors, double-patterning, and advanced packaging are driving growth in the conductor etch market (~$1.6B market in 2010), Thorsten Lill, VP of AMAT's etch business group, explained to SST. Along with advanced processes, however, is the requirement to drive down the cost-per-bit (Figure 1).
Figure 2: Centris etch-matching of 4000 wafers.
The new tool features eight process chambers: six etch and two post-etch clean chambers. AMAT's proprietary software accomplishes chamber matching (Figure 2). Calibration technology is incorporated into the system—when not running product wafers, the system runs auto calibration routines that control pressure and gas flow. "By keeping these processing parameters stable, we also keep the output stable," i.e. the critical dimension (CD), said Lill.
The Mesa process chambers, released in July of this year, feature synchronous pulsing technology that creates a plasma environment to reduce micro-loading. "When we turn the plasma off, we allow the wafer to "relax" electrically, i.e., the charges can dissipate and this reduces one major root cause of micro-loading (mass charging and ion deflection)," Lill told SST. "Basically, the ions' trajectories are distorted and the ions, instead of hitting the bottom of the feature, they hit the sidewall and they either get lost, or you get profile distortions." (Lill offers a more through description of the physics considerations in a podcast at www.electroiq.com/podcasts.html).
End users, particularly the mega-fabs, are pushing for tools that provide ever larger savings on facilitization costs, Lill explained. The company released calculations using standard SEMI S23 methods that indicate an ~35% improvement in energy savings when compared to standard etchers, and lower CO2 emissions per system: equivalent to taking 50 cars per year off the road, said Lill. And one system saves an Olympic-size swimming pool of water per year.
An additional system feature is that bromine (a bromine-containing gas is used during the process) is abated in the load lock, rather than in a separate, dedicated treatment chamber. "This allows us to run six chambers ˆ so the new system, in essence, is an eight-chamber mainframe, said Lill. — D.V.