Decapping

Decapping is usually carried out by chemical etching of the covering,{{Cite web|url=https://www.extremetech.com/extreme/141077-how-to-crack-open-some-computer-chips-and-take-your-own-die-shots|title=How to crack open some computer chips and take your own die shots - ExtremeTech|website=www.extremetech.com}}{{Cite web|url=https://www.semitracks.com/reference-material/failure-and-yield-analysis/failure-analysis-package-level/delid-and-decap.php|title=Delid and Decap | Semitracks|website=www.semitracks.com}} laser cutting, laser evaporation of the covering,{{Cite web|url=https://siliconpr0n.org/wiki/doku.php?id=decap:epoxy|title=decap:epoxy [Silicon Pr0n]|website=siliconpr0n.org}} plasma etching or mechanical removal of the cover using a milling machine, saw blade,{{cite web |last1=Shirriff |first1=Ken |title=555 timer teardown: inside the world's most popular IC |url=https://www.righto.com/2016/02/555-timer-teardown-inside-worlds-most.html |website=Ken Shirriff's blog |access-date=2025-02-04 |language=en |date=February 2016}} using hot air{{Cite web|url=https://hackaday.com/2020/03/11/chip-decapping-the-easy-way/|title=Chip Decapping The Easy Way|date=March 11, 2020}} or by desoldering and cutting.{{Cite web|url=https://wccftech.com/amd-ryzen-threadripper-3970x-3960x-delidding-direct-die-cooling-tested/|title=AMD Ryzen Threadripper 3960X Delidded, Tested With Direct-Die Cooling|date=December 17, 2019}} The process can be either destructive or non-destructive of the internal die.

Chemical etching usually involves subjecting the (if made of plastic) IC package to concentrated or fuming nitric acid, heated concentrated sulfuric acid, white fuming nitric acid or a mixture of the two for some time, possibly while applying heat externally with a hot plate or hot air gun, which dissolve the package while leaving the die intact.{{Cite web|url=https://hackaday.com/2020/10/21/learn-ic-decapping/|title=Learn IC Decapping|date=October 21, 2020}} The acids are dangerous, so protective equipment such as appropriate gloves, full face respirator with appropriate acid cartridges, a lab coat and a fume hood are required.

Laser decapping scans a high power laser beam across the plastic IC package to vaporize it, while avoiding the actual silicon die.

In a common version of non-destructive, mechanical delidding, one removes the IHS of an IC such as a computer processor using an oven to soften the solder (if present) between the IHS and the die(s) and using a knife to cut the adhesive in the periphery of the IHS, which joins the IHS with the processor package substrate, which is often a specialized printed circuit board often only called a substrate or sometimes an interposer. In many processors the dies are also soldered to the IHS which can still be removed by applying heat until the solder melts, and removing the IHS while the solder is still liquid. The die(s) are mounted on the substrate using flip chip.

AMD@7nm(12nmIOD)@Zen2@Rome@EPYC 7702 ES@2S1404E2VJUG5 BB ES DSCx1.jpg|AMD Zen 2 EPYC 7702 server processor, before delidding

AMD@7nm(12nmIOD)@Zen2@Rome@EPYC 7702 ES@2S1404E2VJUG5 BB ES DSCx3.jpg|AMD EPYC 7702 after delidding, with remains of solder thermal interface material (TIM).

AMD@7nm(12nmIOD)@Zen2@Rome@EPYC 7702 ES@2S1404E2VJUG5 BB ES DSCx6 IOD top metal@5x.jpg|Removed and flipped over center die before metallization etching; visible are pads for flip chip solder balls

AMD@7nm(12nmIOD)@Zen2@Rome@EPYC 7702 ES@2S1404E2VJUG5 BB ES DSCx13 IOD polysilicon@5x.jpg|Die shot of the center die, after removal from processor package substrate and metallization etching.

AMD@7nm(12nmIOD)@Zen2@Rome@EPYC 7702 ES@2S1404E2VJUG5 BB ES DSCx16 CCD polysilicon@5xLED.jpg|Die shot of one of the 8 other dies on the processor, after metallization etching.

AMD@7nm(12nmIOD)@Zen2@Rome@EPYC 7702 ES@2S1404E2VJUG5 BB ES DSCx15 IOD+CCD metalsteps notes.jpg|Copper interconnect (metallization) etching (removal) steps

• Die shot
• Reverse engineering
• Sample preparation equipment

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Category:Integrated circuits