L'intégration 3D dans les futurs capteurs d'image · STMicroelectronics 3 ~46,000employees worldwide ~ 7,400 people working in R&D 11 manufacturing sites Over 80 sales & marketing

L'intégration 3D dans les

futurs capteurs d'image

Assemblée Générale IRT Nanoelec

D Thomas

05/03/2019

Plan de la présentation

• ST: qui sommes nous?

• Les imageurs chez ST

• L’intégration 3D pour les imageurs: contribution IRT, réalisations

• Les défis à venir

2

STMicroelectronics 3

~46,000 employees worldwide

~ 7,400 people working in R&D

11 manufacturing sites

Over 80 sales & marketing offices

Among the world’s largest semiconductor companies

Serving over 100,000 customers across the globe

2018 revenues of $9.66B, with year-on-year growth of 15.8%

Listed: NYSE, Euronext Paris and Borsa Italiana, Milan

Signatory of the United Nations Global Compact (UNGC),

Member of the Responsible Business Alliance (RBA)

As of December 31, 2018






4

Imaging Strategy 5

To be the leader in photonic sensors and to become a leader in supplying

specialized image sensor & custom imaging solutionsTime-of-

Flight

Solutions

Specialised

Image

Sensors

Custom

Imaging

Solutions

To provide differentiated Smart Optical Sense & Illumination solutions, thanks to

our advanced pixel & silicon process, optical package & imaging system expertise

Where to find us 6

ImagingSmart Optical Sense & Illumination

Wearable

Appliances

Smart home

Industrial automation

TV/LCD

Medical

Metering

Smartphones

Tablets

Automotive

PC

Robots

ST Pioneer and Leader in Time-of-Flight

7

3 Generationsof all-in-one ToF solution deployed since 4 years

>15 OEMsOver 100 phones with ST’s FlightSense™ technology

>30000Evaluation kits deployed

>500 MillionToF units shipped. Mastering end-to-end supply chain

ST is #1 Worldwide Time-of-Flight sensor supplier

VL53L1 3rd generation FlightSense™

• Multi-target detection

• Programmable multi-zone capability

• Cover-glass crosstalk immunity

China

(Shenzhen)

Applications with FlightSense™… making light work

8

Camera Assist Ranging & Proximity

Presence, User Detect

Today

Gesture Depth Map & AR/VR

LiDAR

Tomorrow






9

3D-Integration: What is the principle?

• From Horizontality to Verticality…

• New system design paradigm: 3D partitioning

10

Wire Bonding

BGA

PCB

Interconnect

RDL

Cu/Low-k

Interconnect

Large Foot-print

L2D

2D Chip SetSystem-in-Package

L3D

Die-scale

RDL

Cu/Low-k

Interconnect

TSV

Interconnect

Block-to-Block Length

1 mm ~ 1 cm 10 ~ 100 mm

3D Chip SetSystem-on-chipS

• Key technological benefits

• Significant reduction of interconnects lengths RC delay decrease

• Heterogeneous integration

• Density vs form factor

Single ChipSystem-on-Chip

Additional gain for image sensor11

Back-Side Illuminated

CMOS image sensor2D

Significant reduction of footprint by partitionning circuit reading

below the pixel matrix

Optimized process dedicated to each silicon layer

Area in the logic die available for Added Value

Stacked

CMOS image sensor3D

Density

201620142010

2,5D Imager TSV last (ST)

3D BSI (Sony)

2,5D FPGA (Xilinx) Hybrid Memory Cube

(Micron)

2012

3D CIS GS (Olympus)

Wide I/O Memory/Logic

(Samsung)

3D MEMS (Bosch)

Hig

hLow

Mid

64Gb 3D Dram

(Samsung)

3D BSI HB

(Sony) Interposer for HBM (AMD)

Photonics (ST)Ambiant Light Sensor TSV last (AMS) Year

Many applications: GPU, MEMS, Memories, Photonics and Image Sensors

Jean Michailos & all, invited paper IEDM 2015

13

3D Products State of the Art

Image Sensors: strong driver for 3D

technologies 14

System Plus

Different integration schemes have been

developed specifically for CIS market

151st Major BreakthroughTSV enabler of (almost) 3D Wafer Level Camera

Permanent glass carrier

Glue

CMOS image sensor

TSV-last SEM view Back-side SEM view

• Permanent glass carrier bonding

• Via last TSV (CD 70µm, depth 70µm)

• Module form factor as main driver

• Surface gain: 33%

• Thickness gain: 50%

3D Wafer Level Camera

2,5D Wafer Level Camera in mass production in 12’’

3Di for BSI Hybrid Bonding (1)

3Di = an active wafer stacked on second active wafer (W2W) for Imagers

Top : Back-Side illumination image sensor

Bottom : ULSI Cmos image readout and processing

16

Face to face interconnections

Double Damascene Copper

stack between top chip last

metal and bottom chip last

metal.

Pitch ≤ 10µm.

Flip

Align

Bond

CMOS

IMG

Back Side

ProcessingThinning, I/O PAD,

Passivation, color, µ-lens…

3Di for BSI Hybrid Bonding (2)

No glue but hybrid molecular bonding

17

Top Wafer

Bottom Wafer

Copper bonding

At 3D-via locations

grain growth/migration by anneal

Direct SiO2/SiO2 bonding

Like in non-3D Back-Side Imager (BSI)

silanol SiOH-SiOH then siloxane Si-O-Si after anneal

Top Ox

Bot Ox

Top Cu

Bot Cu

Via HBV

Bot.

Via HBV

top

3D main challenge - Process flow challenges (1)

• Complex process flow mixing different technology.

• Wafer to wafer alignment criticality.

• Bonding interface quality challenge.

18

YinYang – 93D Demo

• 93D: stacked approach of Pixel array & ISP

19

Computer Vision system:• Face identification

• Gender identification

• Age estimation

• Happiness estimation

• …






20

Further step: Three layers stacking21

Sony ISSCC 2017 and TechInsights May 2017

Frame buffer

in a CMOS

image sensor

High speed

pixel read and

slow output

High speed

binning mode

for movie

Oxide-Oxide

DIECT Bonding +

TSV

Oxide- oxide bonding

Oxide- oxide bonding

Further interconnects density increase

Bonding Challenges ? 22

• First generation of 3D image sensor product is based on ~7 µm pitch

• High density hybrid bonding (1 µm ≤ pitch ≤ 2 µm) could reduce footprint

IMEC:

hybrid bonding 1.8 µm WtW

CEA-EVG :

hybrid bonding 1 µm WtW

Jan 2017 Nov 2017

Bonding Tool

capability

• 1µm pitch requires 50nm precision accuracy

Process integration

• Cu microstructure impact on bonding

• Copper dilatation to be checked for small pad size

• Evaluate impact of wafer to wafer misalignment effect on Cu diffusion

FlightSense™ leveraging ST ecosystem 23

Proximity &

Ranging

User detection

Open.Software

• License SW for single-use on specific

target hardware (STM32 Nucleo

Development Board)

• Click through license on website

STM32 Open

Development

Environment

Algorithms

Sensor fusion

Ultra-low power

connectivity

Documents

L'intégration 3D dans les futurs capteurs d'image · STMicroelectronics 3 ~46,000employees worldwide ~ 7,400 people working in R&D 11 manufacturing sites Over 80 sales & marketing