PART 7 • PACKAGING AND TEST

Packaging and Test

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First-level interconnect

Wire bonding and flip-chip, the two ways in

✅

Test and burn-in

Proving a chip works before it ever ships

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Chiplets

Why some of today's biggest chips are several dies, not one

By the end of this part, you can trace a chip from a diced die to a tested, packaged product.

WHY PACKAGE AT ALL

A bare die is too fragile to use

protect, connect, cool

A finished, diced die is a sliver of silicon a fraction of a millimeter thick, with delicate pads exposed on its surface. A package protects that die from damage and moisture, connects its tiny pads to wires or pins a circuit board can actually use, and gives the heat it generates somewhere to go.

Packaging turns a fragile sliver of silicon into something a board can hold.

THREE JOBS

Everything packaging does, sorted

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Protect

Shields the die from moisture, dust, and physical damage

🔗

Connect

Turns micron-scale pads into pins or balls a board can solder to

🌡️

Cool

Gives heat generated inside the die a path out

Every package design is a balance between these three jobs.

FROM DIE TO PRODUCT

Packaging picks up right where fabrication left off

dice, test, package, test again, ship

A wafer finishes fabrication, gets tested die by die while still whole, and is diced into individual chips. Good die move into packaging, then get tested once more in their finished form before anything ships. Packaging sits right in the middle of that sequence, not at the very end.

A chip is tested twice: once bare on the wafer, and once again, finished, in its package.

UNIT 37 STUDY COMPLETE

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Ready for the Fab Challenge?

You've covered why a bare die needs a package at all: protection, connection, and heat.