op is looking for

It looks like a thick thermal plate undeneath the ssd.

i find these in 3630 part list.  It is 6 mm in thickness.

chat with Dell online to see if these are in stock.

if not consider 6.5 mm thick thermal pad (60x20x6.5 mm) from Dell

I'm running into the same problem. I have a Precision 3630 Tower and I'm trying to install a standard 2280 M.2 NVMe SSD, but I can't find the required thermal pad (Dell part #412-AAQW) anywhere in the USA. I've found the correct part number, but it appears to be out of stock everywhere, and Dell won't ship it from other countries. If anyone has found a compatible alternative or knows where to buy one, I'd really appreciate the help.

followup: i ordered a thermal pad on EBay as it visually seemed to match the one pictured in the installation instructions.  https://www.ebay.com/itm/234195596382.  it is perfect!   However,   i have a new problem, I ordered a screw, part P142N, for the hole at 2280. but  it does not fit into the standoff post at 2280.   The diameter of the shaft of the screw is too large.  Nor, it is probably long enough, as the  standoff post has 4 cross cuts in it, as to accept a Philips screwdriver and the threaded portion is lower than those cutout areas.  The screw sent me as part P147N fits into the larger hole at 2260, but it is too large and too short for the post at 2280

Dell Part Number P142N, M2X2.5MM machine screw, 4.5MM diameter head, Phillips

The Dell screw above is for 3630 motherboard 2260 and 2242 stud.  Op is correct to observe it is not the screw for 2280.

op please describe what thermal pad you ordered on eBay as that link does not come up w an item.  There is another user looking for the thermal pad.

thanks redxps630, typo on my part, the screw is, as you say P142N, it is too thick and short for the standoff post at 2280, although it does fit the hole in the motherboard at 2260.  The standoff post has 4 cross cut openings at the top as if to accept a Phillips screwdriver, the threaded portion is below that area.  Also, visually, the interior diameter looks to be about half that of the P142N screw. Also, it is too short as it needs to go below the top cutout area.  Sales told me they could not help and directed me to technical support who will only provide me with a useless virtual assistant as it is out of warranty.  

https://www.ebay.com/itm/234195596382?itmmeta=01KZCR434815PAY80CF6C3K4AQ&hash=item368725345e:g:YHkAAOSwRn1hR7XS  try this link for the thermal pads  . they measure 20mm X 20MM X 7 MM and are very soft.