Air based selfassembly of silicon chips on foils

Air based self-assembly of silicon chips on foils Name: Coach: Professor: Specialisation: Concern: Coach: Date: B. van Leeuwen Dr. Ir. M. Tichem Prof. dr. U. Staufer Production Technology Holst Centre Prof. Andreas Dietzel, Ph. D 08 -07 -2009 Airflow based self-assembly of silicon chips on foils 1 | 13

Contents • Introduction • Holst centre • Micro assembly • Problem description • Simulation • Dynamic simulation using COMSOL • Dynamic simulation using Matlab • Practical test • Test setup • Test results • Applicability • Results Airflow based self-assembly of silicon chips on foils 2 | 13

Introduction Holst centre • Joint venture of TNO and IMEC-NL • Research in future products • System-in-foil: Low cost, flexible electronics which can be integration in disposable every day products Source: Holst Centre Airflow based self-assembly of silicon chips on foils 3 | 13

Introduction Micro assembly • Problems appearing in micro assembly: • Scaling effect sticking effect • Gripping and grasping difficult (delicate parts): • Solution Self-assembly • Self-assembly: • Processes in which a disordered system of pre-existing components forms an organized structure or pattern. (http: //en. wikipedia. org/wiki/Selfassembly) • Self-assembly can be based on different physical phenomena: • For example: Mechanical, Fluidic or Gas based processes Airflow based self-assembly of silicon chips on foils 4 | 13

Problem description Context • Intelligent package, produced on roll-to-roll production • Placement of flexible chips on flexible foil • Chip placed on first foil, than laminated with second foil • First foil makes placement possible • Second foil takes care of electrodes and connections Airflow based self-assembly of silicon chips on foils 5 | 13

Problem description Context • Multi scale issue (large foil, small chips, accurate positioning) • Ultra low cost, high volume production process Solution: Coarse placement followed by self-assembly • Only air based assembly treated Airflow based self-assembly of silicon chips on foils 6 | 13

Problem description Context • Air flow based self-assembly • Holes in foil will allow air through foil by backside overpressure. • Velocity gradient above surface of foil. • Chip will float and drift to final target location. • Different designs possible • Main problem • Design a foil in a way that: the chip drift to the target location by airflow Airflow based self-assembly of silicon chips on foils 7 | 13

Simulation Dynamic simulation using COMSOL and Matlab • 2 D FEM simulation, solving the Navier-stokes equations using COMSOL. • For different foil designs (velocity profiles) • Obtaining static data • 2 D motion, solving the equations of motion using Matlab. • Data form COMSOL stored in lookup tables • Motion calculated using ODE solver • Motion displayed Airflow based self-assembly of silicon chips on foils 8 | 13

Simulation Dynamic simulation using COMSOL The inlet velocity is imposed at the lower boundary and is defined by the friction of the nozzles: Airflow based self-assembly of silicon chips on foils 9 | 13

Simulation Dynamic simulation using COMSOL Static simulation implemented for a certain chip position Airflow based self-assembly of silicon chips on foils 10 | 13

Simulation Dynamic simulation using Matlab • Storing the obtained data lookup tables, dependent on x, y and φ • Multiple lookup tables for: • Forces and moments • Different velocity profiles. • Not all angle, y-position combinations possible because of geometry Airflow based self-assembly of silicon chips on foils 11 | 13

Simulation Dynamic simulation using Matlab The equations of motion can now be formulated Airflow based self-assembly of silicon chips on foils 12 | 13

Simulation Dynamic simulation using Matlab Solving the equations of motion leads to the moving chip. Airflow based self-assembly of silicon chips on foils 13 | 13

Practical test Test setup Features of test setup • • Overpressure in box by fan Foil attached on top Pressure measurement for feedback Events observed by camera Airflow based self-assembly of silicon chips on foils 14 | 13

Practical test Test results Airflow based self-assembly of silicon chips on foils 15 | 13

Applicability Practical applicability • Integration possibilities • Chip supply • Chip alignment • Chip fixation Airflow based self-assembly of silicon chips on foils 16 | 13

Results • Working simulation software • Dynamic simulation using an array of static FEM calculations • Practical proof of concept • Design and build of test setup • Successful testing of foil design • Practical applicability • Possible integration with other production steps • Manny possibilities Airflow based self-assembly of silicon chips on foils 17 | 13

End of slide show, click to exit. Airflow based self-assembly of silicon chips on foils 18 | 13

Simulation (backup slide) Dynamic simulation using COMSOL Lookup tables for damping in y-direction: • New forces calculated with initial speed • New force subtracted from force without initial speed • Force linearization round zero becomes damping force Airflow based self-assembly of silicon chips on foils 19 | 13

Calculation (backup slide) Airflow based self-assembly of silicon chips on foils 20 | 13