Slurry Design Evolution. Robert L. Rhoades, Ph.D. CAMP Conference Presentation August 14, 2012

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1 Slurry Design Evolution Robert L. Rhoades, Ph.D. CAMP Conference Presentation August 14, 2012

2 Outline Introduction to Slurry Design Birth of a Sub-Industry (Early Years) Slurry Evolution and Revolution Maturing and Forging Ahead Summary 2

3 Author s Note Opinions given in this talk do not necessarily represent the official position of any of the companies or scientists involved in the original work. Opinions also do not necessarily represent this conference, its sponsors, or virtually anyone else. Your mileage may vary. 3

4 Background Slurry is One of the key drivers of CMP performance An essential component of process stability Often the most expensive single ingredient in the cost of consumables Slurry does Provides most of the chemistry for CMP Carries the particles to the interface (most of the time) Strongly influences selectivity 4

5 Slurry Design A few automatic restrictions. Must be aqueous chemistry Avoid extreme ph (above 11 or below 2) No extreme toxins or biohazards A few more preferred design constraints Mild ph (prefer 4 to 11 for most applications) Single component (or very simple mixing) Stable for at least 1 year as shipped Low static etch rates on exposed materials High purity particles and raw ingredients Easy to clean Lowest cost possible 5

6 Early Years Birth of a sub-industry: Mid-1980 s to mid-1990 s Market Trends Immature slurry supply chain Strong growth for the few established suppliers High gross margins for best performers Lots of market entrants attracted by high CAGR Numerous homebrew slurries at early adopter fabs Example Slurries Oxide: Cabot SC-1, Rodel ILD1300 Tungsten: Cabot WA-355/FE-10 6

7 Early Designs General factors impacting slurry design Particle sources often cherry picked from larger volume industries Poor understanding of pad-slurry-film interactions Poor understanding of defect mechanisms Particle wars: SiO2 vs Al2O3 Tolerance for variability was high Most users understood that CMP was immature Design emphasis Application specific formulations Removal rate was often the primary focus for formulation Defectivity important but not dominant in metrics Decisions: Performance then Consistency then Cost (a distant 3 rd ) 7

8 Evolving Years Growth and Evolution: Mid-1990 s to early 2000 s Market Trends Maturing slurry supply chain Continued strong growth for established suppliers Splintering market among fab users inconsistent expectations Declining gross margins for many products Fewer new market entrants, but not much consolidation Most homebrew slurries starting to wane Example Slurries Oxide: Cabot SS-12, Klebosol Tungsten: Cabot SSW

9 Evolving Factors General factors impacting slurry design Some particle sources developed specifically for CMP Improving understanding of pad-slurry-film interactions More customers starting to design for CMP Increasing investment in academic R&D Particle wars: SiO2 vs CeO2 for STI Tolerance for variability was dropping fast Tolerance for rookie mistakes from new suppliers also dropping Shrinking feature sizes drove rapid change in defect requirements 9

10 Evolving Designs Design emphasis Plenty of evolution and a few pockets of revolution Oxide slurries evolved to tighter PSD s and better batch to batch consistency Tungsten slurry saw revolution from Al2O3 with ferric nitrate to SSW-2000 STI slurries first split into 2 camps: Direct STI and STI with REB then underwent revolution to ceria slurries Cu slurries came on strong as the new drivers for both technology and commercial impact, but quickly started seeing price erosion in the market Quest for a Universal Slurry Philosophy was to use a base particle and adjust chemistry for each application Attempted by several manufacturers, at least in R&D labs None of these products were successful in the market Strong pull for slurry concentrates to save shipping costs Ultimate concentrate: Freeze dried slurry Multiple metrics: Rate, selectivity, planarization, defectivity All are important and all have to be met simultaneously Decisions: Consistency then Performance then Cost (a close 3rd) 10

11 Maturing Years Maturing: Early 2000 s to present day Market Trends Mature slurry supply chain Growth now only slightly higher than semiconductor CAGR Some products nearly commoditized No recent new market entrants, but still not much consolidation Each application acts almost like an independent market Few remaining homebrew slurries Splintered market among fab users Leading Edge Still focused on maximum performance (Semi Roadmap) More than Moore Extreme cost focus, stay with proven process technology New Devices New materials, new markets, uncertain volumes 11

12 Maturing Factors General factors impacting slurry design Extreme price increases for CeO2 (moderating lately) Improved understanding of pad surface texture (& pad conditioning) Particle wars mostly subsided Tolerance for variability nearing zero in advanced architectures Many fab engineering teams are now very short staffed Fabs expect suppliers to provide stronger applications support Suppliers are strongly entrenched at key accounts leading to fewer slurry conversions once a process flow is qualified 12

13 Maturing Designs Design emphasis Splintered market drives splintered slurry design goals Leading Edge Defectivity is king, low rates for ultrathin films More than Moore Willing to trade some performance for lower cost New Devices New materials and wildly different performance demands Process engineers like tunability. BUT Perceived as increasing variability and risk of scrap Once optimized, they prefer to receive slurry mixed for their particular blend Decisions: Depends somewhat on target market, but generally is now Cost with Performance and Consistency being a given 13

14 What s Next? Slurry designs will continue to evolve, but in different ways depending on the target market Leading Edge Performance is still premium More than Moore Costs will drive toward commodity slurries New Devices New applications drive strong innovation Defectivity is king Cost is queen 14

15 Acknowledgements Many thanks to the following: Terry Pfau, Paul Lenkersdorfer, Donna Grannis of Entrepix Customers and colleagues for valuable inputs and insights For additional information, please contact: Robert L. Rhoades Entrepix, Inc. Chief Technology Officer

The ABC s of CMP for DWB and SOI. Robert L. Rhoades, Ph.D. CAMP Conference Presentation August 9, 2010

The ABC s of CMP for DWB and SOI Robert L. Rhoades, Ph.D. CAMP Conference Presentation August 9, 2010 Outline Introduction Direct Wafer Bonding (DWB) Background CMP for DWB Silicon-On-Insulator (SOI) Background