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WELCOME1

CAPACITIVE PRESSURE SENSING PCBPresented by :Aparna R.Roll no : 51Guided by:Muhzina Moideen

This presentation includes ,INTRODUCTION.DESIGN.FABRICATION PROCESS.EXPERIMENTAL RESULTS.

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This presentation includes ,Process flow diagram.+ve & -ve photo resist.Root principle.Relaxation oscillator.

Photolithography.Fabricated sensor.Exp. Setup.Results.

Figures included4

IntroductionPCBMEMS Technology.FR4.Photo resist.

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PCBMEMS Technology1. Micro Electro Mechanical Systems (MEMS) The technology of very small mechanical devices Made up of components between 1-100 mm in size Consist of a central unit, the mP and Micro sensors. Basic techniques are Deposition, Patterning & Etching

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PCBMEMS Technology2. Materials used

Silicon Polymers Metals Ceramics7

PCBMEMS Technology

CopperPhoto sensitive covering

Exposed to uv rays

remainingmaterialsetched off

Process Block Diagram8

FR4

Popular And Versatile High Pressure Thermoset. With zero water absorption. Retains insulating qualities in dry & humid conditions. Made of woven fiberglass cloth with an epoxy resin binderWhat is..?9

FR4 ParameterValueSpecic gravity/Density 1850kg/mWater Absorption -.125" < .10%Temperature Index 140 CBond Strength > 1000kgDielectric strength 20 kV/mmProperties10

ApplicationsFR4

Printed circuit boards Relays Switches Transformers11

Photo resistWhat is..? A light sensitive material to form patterned coating on a surface. Classified as Positive and Negative Photo resist.

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Photo resistWhat is..? Positive photoresist: the light exposed portion becomes soluble while the unexposed remains insoluble.

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Photo resistWhat is..? Negative photoresist: the light exposed portion becomes insoluble while the unexposed is dissolved.

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Photo resist

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Photo resistCHARACTERISTICSPOSITIVE NEGATIVE Adhesion to SiliconFairExcellentRelative CostMore expensiveLess expensiveDeveloper BaseAqueousOrganicMinimum Feature