Deposition of hermetic glass thin films for Opto and MEMS

Transcription

1 Deposition of hermetic glass thin films for Opto and MEMS Dr. Ulli Hansen 1

2 Company Profile Founded in 2006 Headquarters and Production in Dresden, Germany Production and R&D Location in Berlin, Germany ISO 9001 certified Worldwide services Funded by German VC 2

3 What we do Hermetic Structured Borosilicate Glass Layers for Packaging of Opto-electronics, MEMS, MOEMS on Wafer-Level 3

4 Key advantages Hermetic Structured Borosilicate Glass Layers as known from lab equipment excellent chemical resistance very low moisture absorption transparent, temperature-stable hard, scratch resistant 4

5 Key advantages Hermetic Structured Borosilicate Glass Layers film thicknesses of 100nm 20µm adhesion verified on various surfaces 3µm glass layer on KOH-etched Si-groove non-conformal, but precise perpetuation of topography low deposition temperature (<80 C) CTE matched to silicon (~3ppm/K) 5

6 Key advantages Hermetic Structured Borosilicate Glass Layers gentle structuring by lift-off technique protection of surface qualities high degree of design freedom 6

7 Key advantages Hermetic Structured Borosilicate Glass Layers hermeticity proven by: temperature-humidity-storage (THS 85 C/85%, 8000h) Helium leak test (MIL-STD 883 Method 1014) 7

8 Key advantages Hermetic Structured Borosilicate Glass Layers Plasma-Assisted E-Beam Evaporation unique deposition process for glass very low substrate temperatures (< 80 C) yielding dense, transparent glass layers batch processing for various substrate sizes: 4 to 8 8

9 Key advantages Lithoglas Technology Deposition of Borosilicate Glass Thin Films hermetic moisture resistant, long-term stable robust temperature resistant, excellent chemical stability compatible low processing temperatures, RoHS compliant, matched thermal behavior to silicon mature controlled layer stress, uniformity, repeatability 9

10 Solutions: surface passivation anodic bond layers semi-finished products cap wafers wafer-level-capping bonding service 10

11 Surface Passivation Immediate protection of chip surface Lithoglas Coatings hermetic sealing of chip surface by thin glass film Glass! application on wafer-level in cleanroom environment structuring of glass by gentle lift-off processing reduced packaging effort / costs typ. appl.: optical sensors 11

12 Anodic Bond Layers Glass Coating of Customer Wafers for Anodic Bonding Lithoglas Coatings borosilicate glass coatings on silicon, quartz, sapphire acc. to customer specification typ. appl.: anodic bond silicon-to-silicon or other materials Source: GE MEMS Sensor Silicon with Lithoglas wafer sizes up to 8 Lithoglas on structured silicon e.g. replacement of glass wafers in MEMS 12

13 Anodic Bond Layers Glass Film Composition Lithoglas Coatings significant sodium content present to enable anodic bonding Investigation of alkaline ion content by EDX/WDX peaks of sodium (Na) and potassium (K) clearly visible 13

14 Anodic Bond Layers Anodic Bonding Example Silicon-to-Silicon Lithoglas Coatings bonding of silicon to silicon (8 ) with 5 µm glass film (on 100nm SiO2) bonding with 3 voltage steps: 20 V, 40 V, 60 V bonding temperature: 400 C bonding time: 10 min moved charge > 1000 mc Deposited Lithoglas Film Bond Chart 14

15 Semi-Finished Products MEMS Cap Wafers Lithoglas Substrates glass film on etched silicon structures for hermetic encapsulation cavity heights of several 100 µm typical lateral dimensions > 5 µm (recommended) typ. appl.: MEMS inertial sensors, MEMS microphones Glass Bond Layer e.g. replacement for glass frit or eutectic bond 15

16 Semi-Finished Products Opto Cap Wafers Lithoglas Substrates structured glass film on transparent substrates cavity heights of 10 to 20 µm typical lateral dimensions > 5 µm (recommended) typ. appl.: optical detectors, imagers 16

17 Semi-Finished Products Opto Cap Wafers Lithoglas Substrates standard cap material: glass, quartz, sapphire optical coatings like AR, IR, apertures feasible cap designs for wafer-level or COB packaging glass cap opto chip RDL/BGA Wafer-level CSP deposited glass dam glass cap opto chip board bonded glass caps for COB packaging 17

18 Semi-Finished Products Opto Cap Wafers Lithoglas Substrates hermetic optical cap cavity heights of several 100 µm typical optical coatings like AR, IR, apertures feasible typ. appl.: detectors, LED 18

19 Semi-Finished Products Opto Cap Wafers Lithoglas Substrates hermetic optical cap with reflector aluminum reflector coating materials: glass, fused silica typ. appl.: HB-LED, UV-LED 19

20 Semi-Finished Products Micro-Structured Wafers Lithoglas Substrates almost arbitrary structure design glass structures by deposition or etching typ. appl.: HB-LED, MEMS, microfluidics 20

21 Technology Lithoglas Low Temperature Glass Coating proven and widely compatible technology, excellent material properties glass thin films are moisture barriers glass thin films as andic bond interface reduction of package size and packaging costs avoids expensive materials and processes enables new packaging concepts / new products 21

22 Opto Cap Wafers wafer-level-integration or pick&place optical glass caps e.g. for imager packaging silicon glass micro caps e.g. for UV-LED packaging etched glass substrates e.g. for HB-LED packaging wafer-level-capping e.g. for COB packaging of optical devices 22

23 MEMS Substrates for anodic bonding micro glass caps e.g. for micro cavities glass coated substrates e.g. as replacement of glass wafers glass coated silicon cavities e.g. for inertial sensors, microphones etched glass substrates e.g. for pressure sensors 23

24 Thank you! Visit us at booth