wafer-level micro-optics with mechanical featuresmeptec.org/resources/1 - heptagon -...

JSa / 070207 v2.2 p.1Copyright © 2011 Heptagon

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9th Annual MEMS Symposium, San Jose, CAThursday, May 19, 2011

Wafer-level micro-optics with mechanical features

Dr. Jyrki SaarinenCo-Founder and Senior Vice President


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Outline

(1) Introduction to micro-optics (2) Introduction to wafer-level micro-optics(3) Company overview(4) Wafer-level manufacturing(5) Applications(6) Summary


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Outline



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Micro-optics

Refractive micro-opticsAnalog to conventional optics, but smaller and lightere.g. microlenses,

microlens arrays

Diffractive micro-opticsEnables functionality not possible with conventional opticse.g. pattern generators,

complex beam shaping

Micro-optics means flat optical elements (refractive and diffractive) with features in the sub-mm or sub-um range, which are fabricated mainly by state-of-the-art lithographic methods


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Micro-optics (cont.)

e.g. Fresnel microlenses, where properties can vary from refractive to diffractive depending upon relief height

Refractive: low spectral dependence well-suited for broad-band illumination

Diffractive: highly accurate focal length well-suited for uniform microlensarrays

Continuous transition from refractive to diffractive optical function in many cases

Also integration/mixing refractive and diffractive micro-optics together or side-by-side


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Outline



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• Invented in 1947• # of transistors: one

Revolution of microelectronicsFrom transistor To Integrated Circuit (IC)

• Invented in 1958• # of transistors: >>1M per mm2

• Production in 300-mm diameter wafer


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400 BC Invention of lens

Why not in optics, too?

1950‘s Injection-molded plastic lensMass production: few tens of lenses per shot

1980‘s Molded glass lensRobustness

2006 Wafer-level (6“) UV replication for reflowable singlet lenses at Heptagon Switzerland

2008 Wafer-level (8“) UV replication and stacking for reflowable doublet lens systems at Heptagon Singapore

Few thousand glass-like lenses per shot and wafer-level assembly for lens systems by stacking:


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Wafer-level optics (WLO)

Silicon wafer Heptagon‘s optics wafer• Single or double sided• Variety of substrates (e.g., fused silica,

borosilicate)• Metal and thin-film coatings (e.g., IR-cut-

off filter, anti-reflection coating)• Stacking with spacer wafers• Stand-off wafers / bottom spacers• NEW: Mechanical features, alignment pins


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Direct integration in SMT assembly process, lead-free reflow, 3×260ºC

Accelerated moisture resistance (>1000 hrs, 85ºC/85%, R.H.), Telcordia proven

RoHS compliance

Small XY footprint and low z-height

1000’s of components per wafer, high throughput, high quality and fidelity

8” wafer processing

Wafer-level stacking and assembly

Micro-optics enabling high performance (efficiency and uniformity), flexibility for beam shaping, and attractive cosmetic appearance

Platform for future technologies, e.g., computational imaging

Reflowable&

Small

ParallelProcessing

Scalability&

InnovationLow Cost

Value propositions


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Outline



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Sales & MarketingManufacturing

R&D FacilitiesSales & Marketing

Sales & Marketing

Company overview

• Pioneer and world-leader in designing and manufacturing wafer-level optics: diffractive optics and micro-optics

• Locations: Switzerland & Singapore & USA• First to industrialize wafer-level optics back in 2006• Key customers: mobile phone & data communication component

OEM’s• Shipped >200M optics components to date, reaching 500M in 2011• Highly yielding optics with a proven manufacturing capability• One-stop shop: from optical design to high volume manufacturing


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Outline



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Production chain

1st gen. replication tool

Mastering /Wafer-level mastering

Submasters

2nd gen. replication tool

x,y,z

Step-and-repeat wafer-level mastering


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Wafer-level UV replication

Optional: coating

At room temperature!No extra pressure applied!


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• Separating single or double sided optical wafers from each other by correct amount optical systems, like lens doublets, triplets etc.

• Separating optics system from sensor or light source by correct amount

• Heptagon developed replication technology for spacer wafers: enables low-cost and robust glass-like polymer spacers

Glass wafers with lenses

Replicated spacer wafers

AB wafer

Spacer 1

CD wafer

Spacer 2

Cross-section

AB wafer

Spacer 1

CD wafer

Spacer 2


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Alignment in xy direction

Background:

WLO manufacturing technologies were developed first for optics, extension to mechanical features recently explored with positive results

Mechanical features (on both sides of a wafer) for passive alignment in assembly

Option 1: Replicating the mechanical features in the same step and materials as the micro-optics

Option 2: Combine WLO with SU-8 features, which are fabricated using standard micro-electronic photolithography equipment for a good positioning accuracy with respect to the WLO and for good control of the geometry

Note: Depends on the specifications and materials.


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12° slanted walls on a 150-um thick alignment feature

100-um cylinder (top), 150-um pitch, 12° angle, 150-um height


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2×12 micro-lens array with 2-sided alignment features

Diameter 700 um; thickness 300 um


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Precision dicing

• Cutting stacked wafers into individual optical systems by precision dicing


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Outline



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Diffractive optics and micro-opticsby Heptagon since 1990‘s


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Reflowable lens moduleOptical axis

Lens A Cr A ApertureIR filter

Glass 1

Plastic spacer 1

Plastic spacer 2

Glass 2

CMOS Sensor

Lens B

Lens C

Lens D

Cr C Aperture

Lens yard


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CIF+ lens modules (singlets)

footprint: 1.7× 1.7 mm

TTL 2.7 mm

Injection molded barrel & mount (reflowable LCP material)

MTF yield on wafers >98%

2,000 lenses per wafer

Sensor with 3.6-um pixel

Volume production since 2006


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No-focus VGA lens modulesVGA doublet

VGA singlet

TTL: 2.1 mmfootprint: 2.4 × 2.4 mm

• No-focus: no adjustment of focal length after assembly (no barrel&mount needed)

• Includes IR cut-off filter, apertures, baffle and stand-off for assembly without extra holder

• Mechanical dimensions optimized for direct mounting (semi-wafer-level assembly) on TSV sensors

• Optical resolution meets typical specs for primary and secondary VGA cameras (1/10” and 1/13”)

• Image quality at least on par with glass or injection molded lens systems



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No-focus 2 MPix lens modules

• 2-wafer solution for entry level 2 MPix cameras

• No-focus: no adjustment of focal length after assembly (no barrel&mount needed)

• Includes IR cut-off filter, apertures, baffle and stand-off for assembly without extra holder

• Mechanical dimensions optimized for direct mounting (semi-wafer level assembly) on TSV sensors

• Image quality comparable to glass molded lenses (2G)

• No AR coating on lenses required



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Fresnel Lens Heptagon Lens

Cos

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Per

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LED flash lenses

Normalized irradiance as a function of x and y position

x position [mm]

y po

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m]

-500 0 500

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-400

-200

0

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6000.2

0.4

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1.6

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Heptagon's LED flash lens based on micro-optics has better visual appearance

higher efficiency at lower heightshigher uniformity and irradiance control


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WLO for data communication• Heptagon is changing the industry paradigm by offering replicated wafer-

level micro-optics as a low-cost alternative to etched fused silica components

• Possibility to fabricate refractive and diffractive micro-optics in a single technology step

• Possibility to include high-reflection and anti-reflection coatings• Telcordia compatible


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Summary WLO is cost-effective high-volume production method Diffractive optics and refractive micro-optics enable

sophisticated, but miniaturized (flat/small height and small footprint) control and modification of light

Easy pre and post processing (e.g., metal and thin-film coatings) in wafer-level for miniature optics

Stacking wafers with spacer wafers allows manufacturing of thousands of more complicated optical systems in parallel

Mechanical features, like alignment pins, enable accurate passive alignment

Heptagon’s WLO is Telcordia proven, lead-free reflow compatible, and RoHS compliant

Heptagon is already manufacturing tens of millions of optics components in applications like, CMOS imaging, LED lighting, and optical data communication


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pany www.heptagon.fi

Thank you!

Jyrki SaarinenSan Jose, [email protected]. (415) 624-4343

wafer-level micro-optics with mechanical featuresmeptec.org/resources/1 - heptagon -...

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