ALICE Silicon Strip Detector Module Assembly with Single-Point TAB Interconnections 1) Introduction 2) Collaboration 3) ALICE SSD module 4) Assembly phases 5) Single-Point TAB interconnections 6) Bond quality assurance a) pull tests b) bond breaking mechanisms and bond strengths c) electrical tests 7) Thermal cycling studies 8) Assembly status M.Oinonen at LECC 2005, Heidelberg, 14 th of September 2005

Si strip detectors at ALICE ITS ALICE ITS: 2 pixel, 2 drift and 2 strip (SSD) detectors layers, 1698 SSD modules with 2.6  10 6 channels, > 7  10 6 bonds ALICE ITS Minimization of mass: thin and flexible structures used with polyimide-Al cables Flexible interconnections based on Ukrainian technology (space and military industry)  strong role of Ukrainian institutes and industry pixel strip drift M.Oinonen at LECC 2005, Heidelberg, 14 th of September 2005

ALICE SSD Collaboration IreS, Strasbourg: HAL25 front-end chips, sensors, module assembling, database, general coordination NIKHEF & Utrecht: general coordination & quality control, design of cables, test setups, module folding, module readout Kiev & Kharkov: cable and subhybrid design & production, manpower Helsinki: module assembling, long-term reliability studies Trieste: module assembling, sensors and sensor tests Nantes: ladder assembling M.Oinonen at LECC 2005, Heidelberg, 14 th of September 2005

Assembly phases / 1 Kharkov Helsinki, Strasbourg, Trieste M.Oinonen at LECC 2005, Heidelberg, 14 th of September 2005

Assembly phases / 2 Helsinki, Strasbourg, Trieste M.Oinonen at LECC 2005, Heidelberg, 14 th of September 2005

ALICE Silicon Strip Detector module Thin and flexible interconnections with Al-polyimide cables Readout via flexible hybrids on both N and P side Double-sided sensor with 2 x 768 channels = 1536 detectors 2 x 6 HAL25 front-end Chips on Flex (CoF), 128 ch’s each M.Oinonen at LECC 2005, Heidelberg, 14 th of September 2005

Assembly phases / 3: Folding M.Oinonen at LECC 2005, Heidelberg, 14 st of September 2005 To be able to install the modules in ladders Challenges the quality of spTAB interconnections ! Helsinki, Strasbourg, Trieste

Production line equipment / Helsinki (see: - semiautomatic bonder (Kulicke&Soffa 4523AD) - automatic bonder (F&K Delvotec 6400) - movable (XYZ) & rotary (  ) bond head  flexible x 150 mm bonding area with 1  m resolution - ultrasonic TAB and wire bonding ( wires) - vacuum oven - ovens (Memmert ULP 400 and UM 200) - X-Y-Z table with Labview control - pressure dispensers - microscopes (50 x – 500 x) - N2 chambers for storing  line for ALICE SSD module production M.Oinonen at LECC 2005, Heidelberg, 14 th of September 2005

Single-point Tape-Automated Bonding (spTAB) Bond Etched window Bonding pad Al lead Chip/sensor Polyimide One bond at a time by using ultrasonic bonding machine and a special wedge Modified wirebonders used with 60 kHz US frequency: F&K Delvotec 6400 (aut) K&S 4523AD (man) M.Oinonen at LECC 2005, Heidelberg, 14 th of September 2005

Bond quality assurance / methods 1) Pull tests a) Manually with a gramometer b) PC controlled with a special setup 3) Electrical tests Operation of the protection diodes in the HAL25 chips (chip bonds) Operation of hybrids (hybrid bonds) Noise characteristics (sensor bonds) 2) Optical 3D tests Understanding of the bond failure mechanisms Spin-off: search for nondestructive & 3D techniques for quality control M.Oinonen at LECC 2005, Heidelberg, 14 th of September 2005

Quality assurance / pull tests 1) Chip & cable with one bond 2) Vacuum stage 3) Pull hook with step motor control 4) PC controlled scale Both manual and PC controlled pull tests give consistent results M.Oinonen at LECC 2005, Heidelberg, 14 th of September 2005

Quality assurance / pull test results Bond typeTrace width (  m) Trace thickness (  m) Max. pull strength (gf) High quality bonds (gf) Chip i/o > 5-6 Sensor > 5-6 Subhybrid > 8-9 Experience: such a high quality bond has less probability to fail under folding operations and thermal cycles compared to the bonds with lower pull strength M.Oinonen at LECC 2005, Heidelberg, 14 th of September 2005

Quality assurance / failure modes a) Lift-offs and heel breaks in pull tests b) Weak bonds or non-attachments during mass production due to contaminants or cable geometry (bending, narrow bond openings) M.Oinonen at LECC 2005, Heidelberg, 14 st of September 2005

Spin-off developments Scanning White-Light Interferometer in fast and non- destructive bond quality control [1] [ 1] H. Seppänen et al., Scanning White-Light Interferometry in Quality Control of Single-Point Tape Automated Bonding, in the Proceedings of the SPIE International Symposium Photonics North, September 27-29, 2004, Ottawa, Canada. M.Oinonen at LECC 2005, Heidelberg, 14 st of September 2005

Quality assurance / optical studies Excess of US power or bond force  overdeformation  small height, low pull strengths  heel breaks / open circles a) lack of US power / bond force b) contamination / geometry problem  high bonds, low pull strengths  lift-offs / closed circles Both modes present at the maximum pull strength M.Oinonen at LECC 2005, Heidelberg, 14 th of September 2005

Quality assurance / lift-off patterns Largest strength reached when part of the trace is left attached on the pad: typical for a good spTAB bond in ALICE SSD application Selection of lift-off patterns used to develop the bond process for the SSD chip bonds (F&K Delvotec 6400). US power (m.u.) Lift-off pattern Failure typelift-off heel- break/(parti al lift-off) Pull strength (gf)3,56,09,08,5 M.Oinonen at LECC 2005, Heidelberg, 14 th of September 2005

Quality assurance / electrical tests for Helsinki chip bonding process On average 99,74 % bonding yield after first-go (incl. dip!) Dip of 92% due to contaminations and cable geometry (new facility) M.Oinonen at LECC 2005, Heidelberg, 14 th of September 2005

1) Bond failures tend to start from the end of the bond rows Thermal expansion most probable cause Thermal cycling studies: induced failures 2) Bonds made during “dip” of 92% yield fail earlier  Bonding quality DOES matter ! M.Oinonen at LECC 2005, Heidelberg, 14 th of September 2005

Thermal cycling studies for Time-to-First-Failure (TTFF) Chip bondsFramed chips Subhybrids Test locationFMI/ HIP FMI/ HIP SRTIIEHIP samples  T test (  C) N cycles >782 >150>389 m TTFF(years)>>20 >9.6>12.3 FMI = Finnish Meteorological Institute, Helsinki HIP = Helsinki Institute of Physics, Helsinki SRTIIE = Scientific Research and Technological Institute of Electronics Engineering, Kharkov Note! JEDEC JEP122B consistently followed in these studies M.Oinonen at LECC 2005, Heidelberg, 14 th of September 2005

ALICE SSD framed chip production (10 th of Sept, 2005) Quality Q = 100- defected channels Yield defined as components having Q > 98 LocationBondedYield (%) HEL STR TRI total M.Oinonen at LECC 2005, Heidelberg, 14 th of September 2005 The same yields in all the sites!

ALICE SSD hybrid production (10 th of Sept 2005) Quality Q = 100- defected channels Yield defined as components having Q > 90 LocationBondedYield (%) HEL STR TRI total M.Oinonen at LECC 2005, Heidelberg, 14 th of September 2005

ALICE SSD module production (10 th of Sept 2005) Test setup just taken in use within the collaboration: no reliable yield yet available ! Losses most probable, since the most challenging operations ahead: folding, ladder assembly etc. Anyway, success in chip & hybrid assembly shows the spTAB process OK M.Oinonen at LECC 2005, Heidelberg, 14 th of September 2005