EV Group 300mm Wafer Bonding Technology July 16, 2008

Transcription

1 EV Group 300mm Wafer Bonding Technology July 16, 2008

2 EV Group in a Nutshell st Our philosophy Our mission in serving next generation application in semiconductor technology Equipment supplier for the semiconductor and MEMS industry equipment installations Privately held company founded in 1980 Headquartered in Austria - subsidiaries in USA, JP, KR and TW Worldwide Sales and Customer Support Network Internal process development (2000m 2 class 100 cleanroom) 20% of revenue is invested into R&D annually

3 EVG core competences GEMINI IQ Aligner NanoSpray Coater DUV Exposure Courtesy of CEETAM TSV: Coating of highaspect ratio vias with dielectrics or photoresists

4 Innovations in Wafer Bonding 1990 First EVG Wafer Bonder with Process Separation Align - Bond First 150mm Bonding System with top and bottom side heating First Bonder with 40kN Piston Force First 200mm Bonding System; Introduction of SmartView Technology 2000 Double-side water cooling; First UV Bond System with optical alignment 2002 First 300mm Bonding System 2003 First system for LowTemp plasma activation 2003 First Chip-to-Wafer System with controllable center of gravity 2005 Second generation (IS) double-sided water cooling system 2005 First Bonder with 60kN Piston Force 2008 First 300mm production bonding system Third generation 100kN double-sided water cooling system SmartView NT Aligner

5 Wafer bonding for 3D integration Cu/Cu SOLID process Top wafer Courtesy of Courtesy of INFINEON Technologies Cu/BCB Via-First BCB BCB SiO2 Cu Fusion bonding 1 µm SiO2 Courtesy of Si LowTemp plasma activation

6 Wafer Bonding Process Separation Principle

7 SmartView Aligner Face-to-face wafer alignment with alignment keys in bond interface Patented Technology Integration with production wafer bonding system GEMINI Product development history 1 st 200mm Systems installed in Field st 300mm Systems installed in Field st GEMINI production bonder st GEMINI with Cleaner st GEMINI with LowTemp Plasma Activation st GEMINI for Transparent Packaging st GEMINI contained in N2 environment 2006

8 SmartView Aligner Working Principle To p Side Objective Bottom Wafer Alignment in contact plane Locate bottom wafer alignment marks with top objectives Lock microscope position Store bottom wafer position Top Wafer Bottom Side Objective Align top wafer to bottom objectives No microscope movement No re-focussing Positioning System Bring wafers in contact Restore bottom wafer position Contact plane = alignment focal plane No blind movement

9 Analysis of contributions to alignment error 1. Translational misalignment 2. Rotational misalignment 3. Run-out Thermal expansion mismatch between top and bottom wafer

10 Post bond metrology Electrical vernier structures generate alignment vector plots NPCQ2B4785 wafer B SEE1 tested , 3 Statistical process control Shift Rotation Run-out 2, , , 2 1, 2 1, 2 1, 2 RMS misalignment 3.2 um Average offset code 0.4, 2. 90% valid 81% X valid 100% Y valid 1, 2 1, 2 1, 2 1, 2 Greyed arrows and values of 99 or -99 indicate that one or both tests gave invalid results at that position. A grey arrow is drawn if one test was valid and so incomplete direction Analysis of impacting factors Bond process parameters 2, 1 2, 0 2, -2 2, -3 1, -4 information is available. A grey open circle is drawn if both tests were invalid and no direction information is available. NPCQ1A4613 wafer B SEH2 tested Bond layer (Reflowing material, surface properties,..) 0, 1 0, 1 0, -1 0, -2 0, -3 1, , RMS misalignment Technical implementation GEM300, SECS II/GEM Wafer ID Bondtool ID Bondchamber ID,.. -1, 1-2, 1-3, 1-1, 0-2, 0-4, 0-4, 0-5, 0-1, 0-2, -1-3, -1-4, -1-5, -1-1, -2-2, , -2-4, -3-5, -4 0, -3-2, -3-3, -3-4, -4-5, -4 0, -4-2, -4-3, -4-4, -4-1, -6-2, -6-3, um Average offset code -1.7, % valid 98% X valid 95% Y valid Greyed arrows and values of 99 or -99 indicate that one or both tests gave invalid results at that position. A grey arrow is drawn if one test was valid and so incomplete direction information is available. A grey open circle is drawn if both tests were invalid and no direction information is available.

11 Bonding Methods / Alignment Capability Alignment System Capability Alignment Method Alignment Accuracy at 3 Sigma Transparent Wafer +/- 0,5 µm Backside Alignment +/- 2µm SmartView Face-to-Face Alignment +/- 1,3 µm Post Bond Alignment Accuracy - Add to Alignment System Capability Bonding Technology Remark Alignment Accuracy at 3 Sigma Anodic Bonding Optimum Contrast Metalized Alignment Key, 4" Wafer, CTE +/- 1µm matched bond glass Glass Fritt Bonding ** 10µm screen printed glass fritt, Ferro , compressed to 4-6µm during bonding process, 150mm or 200mm +/- 5µm Wafer Polymer Thermo Compression Bond Thin spin coated adhesive (<1µm), 150 or 200mm Si-wafer +/- 0,6µm Fusion Bonds (Si + Si, SiO2+SiO 2 ) +/- 0,4 µm Metal Intermediate Layer Thermo Compression Bond Thin (<2µm) metal layer to form an eutectic bond or metal to metal fusion bond. (such as: Au-Si, Cu-Cu...) +/- 0,6µm ** Also applicable to other thick (>5µm) and reflowing intermediate layers.

12 Roadmap for post-bond alignment accuracy ITRS Roadmap ITRS 2007 High Density Through Silicon via Draft Specification ( ) EVG Roadmap

13 Design of SmartView NT

14 SmartView - NT (Nano Align Technology) Next Technology Generation New Basic Set-up High stiffness and perfect surface preparation New base frame (welded) New additional Nano Alignment Stage Nano steps do- and controllable Compensate misalignments during z-movements New Measurement Systems Laser System Permanent control of movement during alignment No blind movement anymore Continuous improvement program over 5 years

15 Optical System Improvements for ITRS roadmap 1. Optics: Improved microscopes Image quality, resolution, stability 2. In-situ optic calibration Alignment accuracy independent from mechanical setup 3. Pattern recognition: based on synthetic patterns Alignment accuracy independent from pattern variation 4. Signal processing: Digital cameras No disturbances from environment, higher signal-to-noise 5. Statistical Process Control: GEM300, SECS II/GEM

16 Precision Alignment Stage High precision alignment Stage allows movement in X, Y and φ direction Technical Data X: ± 13 µm Y: ± 13 µm Φ: ± 0.08 Min. controllable step: 8 nm Compensate misalignment due to kneeling of tables and/or during movements in Z direction Integrated Measurement System with highest Resolution (nm)

17 300mm production wafer bonding systems EVG560 Up to 4 bond chambers Center-to-center wafer alignment Cassette-to-cassette operation EVG Gemini Combines the EVG560 with the SmartView aligner Optical alignment Integration of pre-processes for wafer bonding Cleaning Plasma activation Adhesive coating

18 Wafer bonding for 3D integration Bonding methods Fusion bonding Thermocompression bonding Metal-metal Dielectric bonding e.g. BCB Hybrid methods Fusion + Cu BCB + Cu Decision criteria Integration scheme Surface properties (flatness, roughness) Alignment accuracy Throughput Ziptronix Direct Bond Interconnect (DBI ), Courtesy of Ziptronix Metal/Adhesive 3D Bonding; Courtesy of RPI

19 Bonding methods for 3D integration Room Temperature pre-bond Fusion bonding Highest alignment accuracy No thermal expansion mismatch Highest throughput Batch annealing Tough surface specs High temperature bonds Thermocompression bonding Easier manufacturing schemes Moderate surface specs Pixel Cross-Section of Functional 3D-integrated, 3-tier APD Focal Plane; Courtesy of MIT Lincoln Laboratory, presented at 2006 ISSCC. CMOS SOI BCB Si Courtesy of Freescale Source: P. Morrow et. al, IEEE Electron Device Letters, Vol. 27, No. 5, May 2006, pp335

20 Comparision 3D Bonding Processes SmartView Aligned Cu-Cu BCB SiO 2 Most Promising Roadmap

21 Comparision 3D Bonding Processes SmartView Aligned SiO 2 bonds are ~35% more accurate today, have best potential for further improvement and provide a 10x faster process. SiO 2

22 LowTemp Plasma Bonding for 3D Integration Fusion wafer bonding is a 2-step process 1. Room temperature pre-bond 2. High temperature annealing Traditional fusion bonding methods require annealing temperatures of C. LowTemp plasma activation enables reduction of annealing temperature down to C. Fusion wafer bonding is ideally suited for 3D integration. Pre-bonding at room temperature enables highest alignment accuracy Bond quality inspection prior to annealing rework possible Low manufacturing costs due to batch annealing Metal ion and particle free bonding Si/CMOS 200mm wafers bonded with plasma activated wafer bonding and annealed at 300 C.

23 GEMINI the modular production platform Plasma Chamber SmartView Aligner EVG560 with 4 Bond Chambers Integration of cleaning chamber LowTemp plasma activation SMIF / FOUP Interface GEMINI for transparent packaging: Coating of adhesives UV bond module Wafer-to-Wafer Bonding

24 Summary EVG SmartView NT Newest generation of wafer bond aligner Highest flexibility for substrate properties Established alignment principle, but new design Roadmap 2009: Oxide bond (300mm) 0.3µm (3σ) Cu-Cu Bond (300mm) 0.9µm (3σ) EVG Gemini Cassette-to-cassette production wafer bonding system Integration of pre-bond process modules Plasma activation Wafer cleaning Supports all bonding methods and materials Polymer based thermo compression bonding Metal thermocompression bonding Oxide bonding

25 Questions? For further discussions please do not hesitate to contact me. Thorsten Matthias Director of Technology, EVG North America Tel.: Semicon West 2008 Booth 5429 North Hall

26 EV Group