Advances and Results in Multi-Sheet EFG-Based Sapphire Crystal Growth

Transcription

1 Saint-Gobain Group, Ceramic Materials Division, Crystals Department : Advances and Results in Multi-Sheet EFG-Based Sapphire Crystal Growth John FRANK Guilford MACK Drew HAVEN Jan BUZNIAK Michel BOYER-CHAMMARD International Forum on Sapphire Market & Technologies Shenzen, September 2015

2 Background Industrial roadmap Material Quality Summary 2

3 History of Sapphire business in Saint-Gobain 1971 EFG Technology invented and patent awarded (Harry Labell Jr.) 1999 Saint-Gobain Group acquires Crystal Products (subsidiary of Union Carbide) 2000-present Continuous development of the EFG technology in Milford, NH, primarily for the Aerospace, Defense and Semicon applications (large sheets, tubes, special shapes) 2012 Investment into Devens, MA facility for LED market (mothballed in 2014 due to poor LED market conditions and exclusivity of Apple- GTAT deal) 1990 Starts sapphire production principally for LED substrates (Czochralski method) in Washougal, OR 2000 Saint-Gobain acquires Saphikon (formerly owned by Tyco) with its factory in Milford, NH 2007 Combines EFG and LED substrates experience into a new proprietary technology specially designed for highvolume, thin sheets (LED, consumer electronics) 2013-present Launch of specific R&D program to address the Cover Glass applications using EFG (A-plane). Continued R&D effort in Milford, NH 3

4 Fundamentals of EFG crystal growth EFG = Edge-defined Film- Fed Growth Near Net Shape Innovative method for die-top surface shaping crystal Near-net-shape process Seeds Crystals Crucible Die Melt A-Plane (Cover Glass) Ability to adapt to required shape / size / orientation Lowest cost for large dimension applications and special shapes/ High quality crystal with low defect density Proven technology and equipment design 4

5 Solutions for Aerospace and Defense - Examples of advancements Aerospace Aerospace Added functionality : EO / Stealth Defense, transparent Armor Projectile Sapphire Glass Glass IR countermeasures Improved crew protection from ballistic threats 5

6 EFG technology characteristics Growth shaped by die section No precious atmospheric pressure Automated seeding controls Simultaneous growth of multiple ribbons Feed material is high-purity alumina (HPA) Scrap recycling enhances material yields One EFG furnace unit 16-tip process seen at the crystallisation front Economic equation fundamentals: Number of ribbons Ribbon width Ribbon length Quality yields / usable area More parts per cycle Low cost per part Lower cycle cost Cycle time Energy efficiency Raw material cost Labor productivity / automation Change-over time Hot extraction 6

7 EFG for Consumer Electronics (A-plane) : Current Status Repeatability Number of ribbons per furnace run Cycle time [min/cover] Ribbon Thickness [mm] 2015 Target 8 Cycle Study Useable Surface Area 64% 75% Seed 16-tips Spreading Full-width ribbons 7

8 Mobile Display Formats Conventional sizes used for SG s internal cost simulation (not client-priviledged information) Smartphone Mini-Tablet Tablet Sapphire Blank: 128 mm x 65 mm 5.0 x mm x 140 mm 8.1 x mm x 175mm 9.6 x 6.9 8

9 Comparison of Growth Technologies : different geometric yields, EFG most promising Kyro 85kg ingot Smart phone Mini tablet Tablet Too small Geometric Yields Kyro 85kg Smart phone (%) Mini Tablet (%) Tablet (%) X X Kyro 200kg ingot Too small Kyro 200kg X X HEM 144kg HEM 144kg ingot EFG ribbon EFG Optimization of geometric yields in boules by using excess material as 2 cores Numbers in Blue: Geometric yield without 2 cores Numbers in Red: Geometric yield with 2 cores 9

10 Saint-Gobain s EFG process for Cover Glass Processes developed by SG Processes co-developed with Customer s supply chain EFG Crystal Growth (*) (*) Denotes Process Step with IPCoverage. Sapphire ribbon cropping and cutting with laser Skin Removal with Fixed Abrasive Lapping (*) Double sided Promising technology on the cost standpoint Simple and efficient process steps, environmentally friendly (no wiresaw!) Proven equipment with 40 years accumulated experience Capital-effective and scalable Lapping Polishing Edge + holes 10

11 Technical Performance Indicators (KPIs) : first, some definitions 2x8 Layout 155 mm Useable Surface Area, %: Inspected by shaped region Losses due to spread area and defects First pass growth inspection: Visible inclusions Deviation from planar Dimensionally unsuitable 1250 mm Cycle time: Total process time - gas purge to harvest Divided by total potential covers grown 88% Useable Surface Area 11

12 KPI results from our EFG process Repeatability Study Q1 2015: all points are taken into account (all data shown) KPI: Usable Surface Area

13 Fighting against remaining losses : usable surface area Usable surface area results from the Repeatability campaign, Q Reject 25% Usable Surface Area 75% 13

14 Further improvements (current R&D Focus) Hot extraction Equipment tested Thermal profile development Micro void layer Modeling Die designs Microvoid Layer 1.6mm 1.1mm 14

15 Optical Properties Transmission in visible wavelength Crackle 1x pull rate Average Transmission nm Perkin Elmer Lambda 900 HPA Vendor 1 1x pull rate HPA Vendor 1 2x pull rate HPA Vendor 2 2x pull rate Process parameters can be tuned for low scattering Dependent on: Raw material Growth rate System impurities High Intensity Sidelight Image 15

16 Concluding remarks EFG technology is best suited for complex sapphire shapes and is also adaptable to largevolume, low-cost production of flat thin sheets Process for thin sheets has been developed, potential is proven EFG offers the best cost position on a like-forlike basis compared to boule technology Process still being fine-tuned : Continuous improvement in useable surface area Mechanical and optical properties understanding Very-large scale industrialization, automation SG is actively engaging with customers and partners in the Consumer Electronics field 16

17 Thank you for your attention