What is Tapeout - And Do You Really Send a Tape to Manufacturing?

We’ve come a long way:

• RTL
• Synthesis
• Place & Route
• STA
• Verification
• Simulation, FPGA, Emulation

And now we’ve reached the most exciting moment in chip design:

Tapeout Or: sending to manufacturing.

This is the stage where the design is “sent to the factory” - and the chip becomes reality.

Why Is It Called “Tapeout”?

In the past, before the digital era:

• The chip design was sent on a magnetic tape
• It was called: Tape
• Sending to manufacturing was called: Tapeout (sending out the tape)

Today, of course, tapes aren’t sent. Large digital files are sent.

But the name remained.

It’s like “recording an album” - even though we no longer record on CDs.

What Actually Happens at Tapeout?

Tapeout is a stage where:

1. The complete design passed all tests
2. The Layout is ready
3. STA passed successfully
4. All bugs were fixed
5. The entire system was tested

And now, the final file is sent to the factory (FAB).

The file is called:

GDSII - Graphic Data System II

This is a format that describes:

• All chip layers
• All transistors
• All wires
• The entire chip structure at physical resolution

This is the “construction plan” of the chip.

Why Is Tapeout So Exciting?

Because:

• It’s the end of a complete process that can take years
• It’s the moment when the design “leaves your hands”
• After this, nothing can be changed
• A mistake here costs millions of dollars

Tapeout is a moment of excitement and also enormous pressure.

Development teams spend entire nights before Tapeout to ensure everything is perfect.

What Happens After Tapeout?

The design arrives at the factory (FAB).

The factory:

1. Checks the file
2. Prepares the Masks for manufacturing
3. Starts the physical manufacturing process
4. Manufactures Wafers (silicon discs)
5. Cuts the chips from the discs
6. Packages them

This usually takes between one to three months.

What Is a Mask Set?

To manufacture a chip, the factory uses masks:

• Each layer in the chip needs its own mask
• The mask determines where there will be transistors, wires, metal
• The manufacturing process uses dozens of masks

The GDSII becomes masks, and the masks become chips.

Is There Still a Chance to Change Something?

No.

After Tapeout:

• The design is frozen
• RTL cannot be changed
• Bugs cannot be fixed
• Any change requires a new Tapeout (= enormous cost)

That’s why development teams do everything to ensure the design is correct before Tapeout.

There are cases where a bug is discovered after Tapeout.

In such cases:

• Sometimes an additional Tapeout is done (Respin)
• Sometimes the bug is worked around in software
• Sometimes the chip simply fails

This is why Verification teams work so hard.

How Much Does It Cost?

Tapeout of a modern chip can cost:

• Old process (28nm and above): Hundreds of thousands of dollars
• Advanced process (7nm, 5nm, 3nm): Millions of dollars
• Complex chip: Tens of millions of dollars

It’s an enormous investment.

That’s why only large companies or well-funded projects can afford it.

What Happens After Manufacturing?

After the chip is manufactured:

1. First samples are received (First Silicon)
2. Testing begins (Bring-Up)
3. Verify the chip works
4. Fix bugs if any (in software or Respin)
5. Move to mass production

And then the chip’s real life begins.

An Analogy to Clear Things Up

Think about building a structure:

Frontend: Architecture planning - how many rooms, how many floors.

Backend: Detailed planning - where each room, where the plumbing.

Verification: Checking everything is correct.

Tapeout: Sending the plans to the construction factory.

After Tapeout: Start building in practice - and the plans can’t be changed anymore.

Summary

Tapeout is:

• Sending the final design to the factory
• GDSII file containing the entire chip
• The moment when the design is “frozen”
• The stage where the chip moves from description to manufacturing
• An exciting and stressful event simultaneously

After Tapeout, the chip is on its way to becoming physical reality.

---

In the next post, we’ll learn about FAB, Bring-Up, and Post-Silicon Validation - what happens in the manufacturing plant, how the first chip is tested, and how you ensure it works as planned.