⚙️ Big Picture: Where Does Assembly & Packaging Fit in IC Fabrication?
IC Fabrication has 3 major phases:
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Front-End (Wafer fabrication) – Transistors and circuits are formed on the silicon wafer.
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Back-End (Wafer test and dicing) – Chips are tested and cut from the wafer.
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Assembly & Packaging – Each chip is enclosed in a protective package and connected to the outside world.
You're here ➡️ 🟨 Phase 3: Assembly and Packaging
🔩 What Happens in Assembly & Packaging?
Let’s walk through it step-by-step:
🧱 1. Wafer Dicing
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The wafer is diced into individual dies (aka chips).
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Done using a diamond saw or laser.
📌 Think of slicing a pizza into square micro-slices 🍕➡️🔲🔲🔲
🖇️ 2. Die Attach
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Each chip (die) is attached to a substrate or lead frame using epoxy or solder.
There are two types:
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Epoxy die attach
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Solder die attach
⚡ 3. Wire Bonding / Flip-Chip
This is how the tiny die connects to the package pins or pads:
🧵 Wire Bonding:
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Fine gold or aluminum wires connect chip pads to package leads.
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Used in traditional packages.
🧲 Flip-Chip:
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Die is flipped upside down.
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Bumps (usually solder) directly connect to the substrate.
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Shorter path = better performance.
🛡️ 4. Encapsulation / Molding
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The die and wires are covered with plastic or ceramic to protect from:
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Moisture
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Heat
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Physical damage
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➡️ This is when your tiny naked silicon chip becomes a neat IC package (like the black rectangle you see on PCBs).
📦 5. Packaging
Common package types:
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DIP (Dual In-line Package)
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QFP (Quad Flat Package)
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BGA (Ball Grid Array)
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CSP (Chip Scale Package)
Each has trade-offs in size, cost, thermal, and electrical performance.
✅ 6. Final Testing & Burn-in
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Packages are tested for functionality, speed, and reliability.
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Sometimes they go through burn-in ovens (stress testing under high heat/voltage).
📚 Want to Learn More?
If you want to deepen your knowledge, here are areas to explore:
Topic | What to Learn |
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📐 Package Design | Thermal management, signal integrity |
💡 Materials | Underfill, solder bumps, molding compounds |
🛠️ Processes | Wire bonding, flip-chip, encapsulation |
🔬 Reliability Testing | Burn-in, thermal cycling, HAST |
🧪 Standards | JEDEC, IPC standards for packaging |
🧭 Motivation Plan for You (If You’re on Bench or Exploring)
🎯 Goal: Get familiar and project-ready in IC Packaging
✅ Week 1-2: Learn the basics
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Watch short videos (Intel, TSMC, Amkor have great ones on YouTube).
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Read intro PDFs from universities (MIT, IIT, or companies like ASE or TI).
✅ Week 3: Pick a topic to dive deeper
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Example: Flip-chip bonding
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Read a whitepaper, maybe build a mini presentation for yourself or LinkedIn post.
✅ Week 4: Project idea!
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Make a presentation, blog, or simple visual guide explaining the flow.
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If you're into CAD: Try basic IC package modeling in Fusion 360 or Altium (even for fun).