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Unformatted text preview: 2/23/06 RCL SMLY Presentation 1 Systematic Mechanisms Systematic Mechanisms Limited Yield Survey Limited Yield Survey Rob Leachman IEOR 130 U C Berkeley 21 February, 2006 2/23/06 RCL SMLY Presentation 2 Background Assess performance and practices at 5 Sematech member companies in systematic mechanisms limited yield (SMLY) improvement Identify BKMs and make recommendations for realizing better practices Study initiated March, 2002 Final report issued March, 2003 2/23/06 RCL SMLY Presentation 3 Agenda Overall yield loss trends Topdown decomposition of overall yield loss into defect and systematic losses Prevalent systematic losses Best practice: bottomup analysis of component losses Recommendations 2/23/06 RCL SMLY Presentation 4 Overall yield loss trends Die yields reported by participants were normalized for die area We assumed half of yield losses arise from systematic mechanisms and half arise from Poissondistributed random defects: Y = Ys*Yr = Ys*exp(AD ) = [(1+Y)/2]*exp(AD ) We solved for D using given die area A and given die yield Y. Then we predicted die yield for A = 0.5 sq cm: DY = [(1+Y)/2]*exp(0.5*D ) We graphed Yield loss = 1  DY*SLY where SLY is the reported sort line yield For this assumption, the yield loss curves of the participants line up remarkably well 2/23/06 RCL SMLY Presentation 5 Figure 2 350 nm Yield Loss Curves 0.1 1 S e p 9 6 J a n 9 7 M a y 9 7 S e p 9 7 J a n 9 8 M a y 9 8 S e p 9 8 J a n 9 9 M a y 9 9 S e p 9 9 J a n M a y S e p J a n 1 M a y 1 S e p 1 J a n 2 M a y 2 S e p 2 1  Die Yield (A=0.5)*Sort Line Yield 2/23/06 RCL SMLY Presentation 6 Figure 3 250 nm Yield Loss Curves 0.1 1 A p r 9 8 J u l 9 8 O c t 9 8 J a n 9 9 A p r 9 9 J u l 9 9 O c t 9 9 J a n A p r J u l O c t J a n 1 A p r 1 J u l 1 O c t 1 J a n 2 A p r 2 J u l 2 O c t 2 1  Die Yield (A=0.5)*Sort Line Yield 2/23/06 RCL SMLY Presentation 7 Figure 4 180 nm Yield Loss Curves 0.1 1 S e p N o v J a n 1 M a r 1 M a y 1 J u l 1 S e p 1 N o v 1 J a n 2 M a r 2 M a y 2 J u l 2 S e p 2 N o v 2 1  Die Yield (A=0.5)*Sort Line Yield 2/23/06 RCL SMLY Presentation 8 The yield learning rate improved at the 180nm node Technology Rate of Reduction in Yield Loss...
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This note was uploaded on 04/02/2008 for the course IEOR 130 taught by Professor Leachman during the Spring '07 term at University of California, Berkeley.
 Spring '07
 Leachman

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