(Replying to PARENT post)

> It’s surprisingly dark, too. For decades, Intel’s cleanrooms have been lit like darkrooms, bathed in a deep, low yellow. “That’s an anachronism,” says Mark Bohr, a small, serious man who has spent his entire 38-year career making chips, and who’s now Intel’s top manufacturing scientist. “Nobody’s had the courage to change it.”

Wait, what? Isn't that UV-free light? Ultraviolet light is used in the mask exposure step, so using normal light in the room would basically remove all of the photoresist before photolithography.

I guess they've automated the process to the point where the wafers are never exposed to light even when moving between steps.

👤Cyph0n🕑9y🔼0🗨️0

(Replying to PARENT post)

This is true. The wafer carrying "foups" mentioned are actually an acronym for Front Opening Unified Pods, which is what carry the wafers from machine to machine in batches of up to 25 wafers at a time. They are typically UV opaque yellow, or black. The wafers aren't ever actually out in the open in the room at any time.

(As an aside, since the air quality of the room was mentioned...god forbid you ever broke a wafer in the foup. Entire lot in that box is ruined, and cleaning the foup itself and the equipment front ends is a giant PITA)

Source: was engineer at Varian Semiconductor / Applied Materials, who make all those giant tools that Intel and the other fabs use. Intel was definitely one of our largest customers and our most technically demanding.

👤TFortunato🕑9y🔼0🗨️0

(Replying to PARENT post)

With a SLA 3d printer you use a filter in the case so UV light is filtered. You can identify those machines because they are colored: https://www.b9c.com/assets/images/bg/bg-home-header.png

By the way the people at Intel are working with ultra UV, and every material is opaque to them. That is the reason for the use of reflection surfaces instead of lenses for new machines.

👤pipio21🕑9y🔼0🗨️0

(Replying to PARENT post)

Or they've moved so damn far into the UV that their photoresist doesn't even care about the wimpy just-beyond-visual peaks coming out of fluorescent lights.
👤jjoonathan🕑9y🔼0🗨️0

(Replying to PARENT post)

They might be referring to the fact that the room might not have photo-resistive materials or the fact that they have not investigated other methods that could allow them to use white light in the room.
👤shivsta🕑9y🔼0🗨️0