PbSn60 Solder Bumping PbSn60 Solder Bumping by Electroplating by - PowerPoint PPT Presentation

Pixel 2000, Genova Pixel 2000, Genova, June 5-8, 2000 , June 5-8, 2000 PbSn60 Solder Bumping PbSn60 Solder Bumping by Electroplating by Electroplating Juergen Wolf Wolf Juergen Fraunhofer IZM Fraunhofer IZM Berlin, Germany Berlin, Germany Fraunhofer Juergen Wolf Institut High Density Interconnect & Waferlevel Packaging Zuverlässigkeit und Phone: +49-(0)30-314-72887 E-Mail: wolf@izm.fhg.de Mikrointegration

Technology: Technology: Solder Bumping Substrate Solder Bumping Substrate Metallization Metallization Si read out chip (6“) Si3N4 passivation Si (4“); 200-250 µm thickness I/O pad size: 12 µm Si3N4 / SiON passivation pitch: 50 µm UBM for FC on I/O Al-pads Al wire bond pads not [thin film multi layer (MCM-D)] bumped no 2 nd soldering level PbSn 60; size: ø 25µm Build up: UBM: Ti:W/Cu/ep.Cu metal: Ti:W/Cu + ep.Cu Electroplating dielectric: BCB (MCM-D) Flip Chip Bonding Flip Chip Bonding Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 E-Mail: wolf@izm.fhg.de

PbSn Solder Bump Structure Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 E-Mail: wolf@izm.fhg.de

PbSn- Bumping - Processflow Sputter Etching and Sputtering Spin Coating and Printing of the Plating Base / UBM of Photoresist Resist Stripping and wet Etching Electroplating of Cu and PbSn of the Plating Base Reflow Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 E-Mail: wolf@izm.fhg.de

PbSn Bumping Process Flow in Detail in Detail PbSn Bumping Process Flow pre-conditioning incomming optical photoresist photoresist (plasma O 2 ) inspection spin on / prebake/ exposure / develope/ pre-conditioning postbake cleaning SRD (etching) sputtering platingbase sputtering platingbase optical inspection electroplating Cu ion etching (Ar) Ti:W (200 nm) / rinse resist thickness (DI water) Cu (300 nm)/ control measurement electroplating optical inspection PbSn60 warp & sheet 3 x rinse resistance control (DI water) # 2 Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 Technische Universität Berlin E-Mail: wolf@izm.fhg.de Research Center of Microperipheric Technologies

PbSn Bumping Process Flow in Detail ( in Detail (cont cont.) .) PbSn Bumping Process Flow # 2 UBM etching Ti:W photoresist photoresist photoresist stripping (1) photoresist stripping (1) (H 2 O 2 ) spin on / bake (aceton aceton) ) ( dicing photoresist stripping (2) photoresist stripping (2) UBM etching Cu (aceton aceton) ) (CuCl 2 ) ) ( resist stripping resist stripping 3x (aceton aceton) ) 3x ( photoresist stripping photoresist stripping (3) (3) optical inspection (aceton aceton) ) ( optical inspection reflow reflow optical inspection (100 %) optical inspection selection & sorting bump shape control high measurement Flip Chip Bonding Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 Technische Universität Berlin E-Mail: wolf@izm.fhg.de Research Center of Microperipheric Technologies

Solder Bumping Pb40Sn60 PbSn60 Solder Bumps (diameter: 25 µm; pitch 50 µm) UBM: Ti:W/Cu / ep.Cu (5µm) Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 Technische Universität Berlin E-Mail: wolf@izm.fhg.de Research Center of Microperipheric Technologies

Solder Bumping Pb40Sn60 after electroplating after Reflow PbSn60 Solder Bumps (diameter: 25 µm; pitch 50 µm) UBM: Ti:W/Cu / ep.Cu (5µm) Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 Technische Universität Berlin E-Mail: wolf@izm.fhg.de Research Center of Microperipheric Technologies

Solder Bumping Pb40Sn60 Read out BiCMOS Si-chip (Uni Bonn) with Solder Bumps (diameter: 25 µm; pitch 50 µm) after Reflow UBM: Ti:W/Cu / ep.Cu (5µm) Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 Technische Universität Berlin E-Mail: wolf@izm.fhg.de Research Center of Microperipheric Technologies

Solder Bump Reflow Oxidelayers must be removed to allow solderball formation Use of aggressive fluxes must be avoided Melting point: T m = 314°C (95/5 wt% Pb/Sn), T m = 183°C (37/63 wt% Pb/Sn Some fluxless reflow methods: Reflow methods: Heating under active atmosphere Heating under reducing atmosphere Using Flux (RMA) - 100 % H 2 - 95 % N 2 / 5 % H 2 ( not sufficant ) ( Reflow in vaccum ) ( Reflow after Sputteretching or RIE) Process: Pb40Sn60 (PbSn5) Heating in a organic medium up to 240 (350) °C followed by cleaning procedure Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 E-Mail: wolf@izm.fhg.de

Solder Bump Reflow Process: Pb40Sn60 (PbSn5) Heating in a organic medium up to 240 (350)°C followed by cleaning procedure Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 E-Mail: wolf@izm.fhg.de

Flip Chip Assembly Process Flow Process Flow Solder Bumping Read out chip Cleaning & Inspection Dicing Inspection Alignment Loading Substrate Loading Chip 4 µm x/y accuracy Placement Unload Module / Unload Module / Inspection Single Tile Single Tile Wettable Metallization Detector Substrate Reflow Soldering 240° C peak temperature, activated atmosphere Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 Technische Universität Berlin E-Mail: wolf@izm.fhg.de Research Center of Microperipheric Technologies

Equipment @ IZM Solder Bumping (6“-8“) Sputtering LLS 802 (Balzers) Lithography ACS 200 (Karl Suss) MA 200 (Karl Suss) Electroplating RIE System Ten 1107 (Matrix) July 2000 EQUINOX (Semitool) Reflow LRP 200 (RENA) Optical Inspection NSX 90 (August) Dicing DAD 341(Disco) Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 Technische Universität Berlin E-Mail: wolf@izm.fhg.de Research Center of Microperipheric Technologies

Equipment @ IZM Flip Chip Bonding Flip Chip Bonder FC 950 (Karl Suss) FC 250 (Karl Suss) X-ray Inspection X-ray (Feinfocus) Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 Technische Universität Berlin E-Mail: wolf@izm.fhg.de Research Center of Microperipheric Technologies

Inspection / Yield / Issues Inspection / Yield / Issues Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 E-Mail: wolf@izm.fhg.de

Optical Bump Inspection Automated Defect Inspection System NSX-90 August Technology Inspection time: ≈ 120 min / wafer all bumps (ATLAS FE-B/D [6“]) Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 E-Mail: wolf@izm.fhg.de

Inspection Sites Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 E-Mail: wolf@izm.fhg.de

Defect Classes Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 E-Mail: wolf@izm.fhg.de

Defect Classes Small Bump Large Bump Particle Particle Bump Missing Position Bump Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 E-Mail: wolf@izm.fhg.de

Bump-Profile for Atlas Bump Inspection Bump Size / Position: Defect Code: Minimum Size: 0.027 mm → → Small Bump → → Maximum Size: 0.032 mm → → Large Bump → → 0.005 mm → → Bump position → → Tolerance +/-: Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 E-Mail: wolf@izm.fhg.de

Bump shear variation as multiple reflows Bump shear variation as multiple reflows µ m size bumps) µ µ µ (25 µ µ µ µ m size bumps) (25 wafer 17 center bump size 25 µ m wafer 17 edge wafer 10 center 20 bump shear force (g) wafer 10 edge 15 10 5 0 1 reflow 2 reflow 3 reflow 4 reflow reflow numbers Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 E-Mail: wolf@izm.fhg.de

Cross-sectional images as multiple reflows Cross-sectional images as multiple reflows reflow 3 reflow 1 reflow 2 Juergen Wolf Cu: 3.6 µ µ m High Density Interconnect & Waferlevel Packaging µ µ Cu: 4.0 µ µ m Cu: 3.8 µ µ m µ µ µ µ Phone: +49-(0)30-314-72887 E-Mail: wolf@izm.fhg.de

High Density Flip Chip Detector Module pixel detector module for proton proton interactions at the Large Hadron Collider at the European Laboratory for Particle Physics Cern Topics: 16 ICs; 46080 PbSn Solder Bumps; pitch: 50 µm Juergen Wolf High Density Interconnect & Waferlevel Packaging Phone: +49-(0)30-314-72887 Technische Universität Berlin E-Mail: wolf@izm.fhg.de Research Center of Microperipheric Technologies