On Thursday, July 9, 2020 at 7:14:37 PM UTC-4, klaus.k...@gmail.com wrote:> Hi > > For fun I need to inspect the die in a typical BC847 SOT23 plastic housing > > How do one decap that transistor? > > Cheers > > KlausFor bigger stuff I like some vise grips and a disk sander. Maybe solder some onto a pcb as a holder? And a dremel? or will that just rip the leads off when you grind away at the top? (you're probably all done by now.) George H.
Decapping a SOT23
Started by ●July 9, 2020
Reply by ●July 10, 20202020-07-10
Reply by ●July 10, 20202020-07-10
On 7/10/2020 1:11 PM, Phil Hobbs wrote:> On 2020-07-10 00:04, jlarkin@highlandsniptechnology.com wrote: >> On Thu, 9 Jul 2020 20:05:47 -0700 (PDT), Phil Allison >> <pallison49@gmail.com> wrote: >> >>> John Larkin wrote: >>> >>> ================== >>>> >>>> Squeeze it sideways in a vice. Sometimes the package will shear apart >>>> and expose the chip. >>>> >>> >>> ** Most likely take to top layer of the chip with it. >>> >>> Happens all the time with TO220 and TO3P paks. >>> >>> Only metal can paks ( TO18, TO5, TO3 etc) are amenable to chip >>> observation. >>> >>> >>> .... Phil >> >> I squeezed these in a big bench vice >> >> https://www.dropbox.com/s/4nxm7m2q3j3buvc/ExFets.jpg?raw=1 >> >> just to see what they looked like, after we blew them up exploring >> analog safe-operating areas. >> >> We found a couple of big switchmode fets that were good as linear >> amps. > > You can also decap a DIP by connecting the mains across the two rows of > pins. Makes a nice crater--point it away from your face when you do it. > > Unfortunately it also ablates the chip. Nice bang though. > > Cheers > > Phil Hobbs > >Certain MSI motherboards have that decapping-mode as a built-in feature for DPAK FETs in the CPU synchronous buck where they half-assed the high-side gate driver and just used a power FET totem pole for the high-side gate driver instead of a integrated thinger. They under-specced it and it can get into a thermal runaway situation when e.g. the CPU fan or liquid coolant loop fails, but before the CPU thermal limiting kicks in. Pop!
Reply by ●July 10, 20202020-07-10
On 7/10/2020 4:22 PM, bitrex wrote:> On 7/10/2020 1:11 PM, Phil Hobbs wrote: >> On 2020-07-10 00:04, jlarkin@highlandsniptechnology.com wrote: >>> On Thu, 9 Jul 2020 20:05:47 -0700 (PDT), Phil Allison >>> <pallison49@gmail.com> wrote: >>> >>>> John Larkin wrote: >>>> >>>> ================== >>>>> >>>>> Squeeze it sideways in a vice. Sometimes the package will shear apart >>>>> and expose the chip. >>>>> >>>> >>>> ** Most likely take to top layer of the chip with it. >>>> >>>> Happens all the time with TO220 and TO3P paks. >>>> >>>> Only metal can paks ( TO18, TO5, TO3 etc) are amenable to chip >>>> observation. >>>> >>>> >>>> .... Phil >>> >>> I squeezed these in a big bench vice >>> >>> https://www.dropbox.com/s/4nxm7m2q3j3buvc/ExFets.jpg?raw=1 >>> >>> just to see what they looked like, after we blew them up exploring >>> analog safe-operating areas. >>> >>> We found a couple of big switchmode fets that were good as linear >>> amps. >> >> You can also decap a DIP by connecting the mains across the two rows >> of pins. Makes a nice crater--point it away from your face when you >> do it. >> >> Unfortunately it also ablates the chip. Nice bang though. >> >> Cheers >> >> Phil Hobbs >> >> > > Certain MSI motherboards have that decapping-mode as a built-in feature > for DPAK FETs in the CPU synchronous buck where they half-assed the > high-side gate driver and just used a power FET totem pole for the > high-side gate driver instead of a integrated thinger. > > They under-specced it and it can get into a thermal runaway situation > when e.g. the CPU fan or liquid coolant loop fails, but before the CPU > thermal limiting kicks in. Pop!Not a gentle pop. More like if the PC box is in the same floor of the house with you that'll definitely wake you up.
Reply by ●July 12, 20202020-07-12
Klaus - I tried methylene chloride with no luck. I'm guessing that heat cured epoxyies are hardier that room temperature cured types. Next step would be a pressure capable container and a heater and a pressure relief valve. Hul klaus.kragelund@gmail.com wrote:> Hi> For fun I need to inspect the die in a typical BC847 SOT23 plastic housing> How do one decap that transistor?> Cheers> Klaus
Reply by ●July 12, 20202020-07-12
On Thu, 9 Jul 2020 16:14:32 -0700 (PDT), klaus.kragelund@gmail.com wrote:>Hi > >For fun I need to inspect the die in a typical BC847 SOT23 plastic housing > >How do one decap that transistor? > >Cheers > >KlausJust curious, why do you want to see the die? -- John Larkin Highland Technology, Inc Science teaches us to doubt. Claude Bernard
Reply by ●July 12, 20202020-07-12
On Sun, 12 Jul 2020 08:09:07 -0700, jlarkin@highlandsniptechnology.com wrote:>On Thu, 9 Jul 2020 16:14:32 -0700 (PDT), klaus.kragelund@gmail.com >wrote: >>For fun I need to inspect the die in a typical BC847 SOT23 plastic housing >>How do one decap that transistor? >>Cheers >>Klaus>Just curious, why do you want to see the die?To watch them die, of course. BC847BS (matched pair). <https://zeptobars.com/en/read/diodes-BC847BS-matched-pair-bjt-npn> or single: <https://zeptobars.com/en/read/Phillips-BC847C-npn-BJT-transistor> More dead dies (including a few possible fakes): <https://zeptobars.com/en/> 31 pages of decapsulated dead dies. There doesn't seem to be a search feature on the web site, but Google search works. Search for: site:zeptobars.com BC847 as in: <https://www.google.com/search?q=site:zeptobars.com+BC847> -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Reply by ●July 12, 20202020-07-12
On Sun, 12 Jul 2020 08:44:14 -0700, Jeff Liebermann <jeffl@cruzio.com> wrote: More: "How to open microchip and what's inside?" <https://zeptobars.com/en/read/how-to-open-microchip-asic-what-inside> Take some microchips of interest and add concentrated sulfuric acid. Container should be closed, but not airtight, so that fumes can escape (that is extremely important). Heat it to boiling temperature (300 �C). White substance at the bottom is baking soda - it's here to neutralize accidental spills and part of fumes. "Part II: How to open microchip and what's inside? Z80, Multiclet, MSP430, PIC and more" <https://zeptobars.com/en/read/open-microchip-asic-what-inside-II-msp430-pic-z80> Put a droplet of fuming nitric or sulfuric acid there, heat up to ~100 �C (~212 �F). It is critical to use fuming acids - just concentrated (98% sulfuric or 70% nitric) won't cut it. After reaction ends - rinse with acetone, dry and put next droplet. As a result we are getting exposed die, with all bond wires intact. The microchip still works - this might be useful if we want to probe it or modify eeprom data with UV laser. Please remember that you have only one life to give for your profession or hobby. Otherwise, this looks like fun. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Reply by ●July 12, 20202020-07-12
Thank you all for your answers and ideas I am on vacation right now but will try when I get back again The BC847 is just an example. What I am actually doing is to evaluate a competitor product of the BC847. I would like to see if the dies are really close to be the same Regards Klaus
Reply by ●July 12, 20202020-07-12
Jasen Betts wrote:> Hot fuming nitric acid: don't try this at home.Home is the keyword: HNO3 in concentrations above 3% is unobtainium for private users per: https://lovdata.no/static/SF/32013r0098e.pdf Specifically, its implementation in Poland is punishable by up to 2 years in prison for both the buyer and the seller. I bet the same curvature of banana geniuses are behind this act as well, as H2SO4 is still legally available in any concentration and transforming it into HNO3 requires maybe 50EUR-worth equipment. So decapping the chip that way can be performed only by a company, sorry. Try boiling formic acid, if suicide is an option. Best regards, Piotr
Reply by ●July 13, 20202020-07-13
On 2020-07-12 11:44, Jeff Liebermann wrote:> On Sun, 12 Jul 2020 08:09:07 -0700, jlarkin@highlandsniptechnology.com > wrote: > >> On Thu, 9 Jul 2020 16:14:32 -0700 (PDT), klaus.kragelund@gmail.com >> wrote: >>> For fun I need to inspect the die in a typical BC847 SOT23 plastic housing >>> How do one decap that transistor? >>> Cheers >>> Klaus > >> Just curious, why do you want to see the die? > > To watch them die, of course. > > BC847BS (matched pair). > <https://zeptobars.com/en/read/diodes-BC847BS-matched-pair-bjt-npn> > or single: > <https://zeptobars.com/en/read/Phillips-BC847C-npn-BJT-transistor> > > More dead dies (including a few possible fakes): > <https://zeptobars.com/en/> > 31 pages of decapsulated dead dies. > > There doesn't seem to be a search feature on the web site, but Google > search works. Search for: > site:zeptobars.com BC847 > as in: > <https://www.google.com/search?q=site:zeptobars.com+BC847> > > >For $5 per month on Patreon, you can send chips to the Zeptobars guy for decapping. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
