News Asus AMD Ryzen 9 7945HX3D Laptop Processor Liquid Metal Mitigations Revealed

[Admin]

Asus has been using liquid metal in laptop cooling systems for years, but the AMD Ryzen 9 7945HX3D design presents new challenges.

Asus AMD Ryzen 9 7945HX3D Laptop Processor Liquid Metal Mitigations Revealed : Read more

 

[Kamen Rider Blade]

We'll find out soon enough how long that Liquid Metal Solder masks holds up in the "Long Term" with in-field usage by real people.

 

[ryankm]

We'll find out soon enough how long that Liquid Metal Solder masks holds up in the "Long Term" with in-field usage by real people.

It works I used it. It dose lose some of it's thermal conductivity over time, but is 10 times better than typical thermal paste so this negligible. It is like solder and there is a burn in process. This just means you cant knowck the cooler or whatever because it will break the solder. I myself switched to indium foil pads. It is about the same as liquid metal except is non toxic and easy to clean up and doesnt break down either. Way easier to just put and indium pad on than go through the careful process of applying liquid metal.

 

[edzieba]

Solder mask, or a similar non-conductive barrier like a lacquer or epoxy resin

The term you're looking for is 'Conformal Coating'. That's what is applied to a populated PCB assembly to protect it from external chemicals (be it water, corrosive gases, corrosive compounds like 'liquid metal' pastes*, etc). Solder mask is applied to the bare PCB prior to population.


* Liquid Metal TIM is an eutectic Gallium alloy. Gallium is well known for its propensity to infiltrate other metals, and Gallium also attacks Silicon. The backside of a die is normally protected by a layer of Nickel with a thin Gold coating (the Nickel wets to the solder TIM well, the Gold protects the Nickel from oxidisation as Nickel oxides do not wet the solder), but against attack by Gallium only the Gold coating is doing any good, the underlying Nickel is vulnerable to attack just like the Silicon die.
My concern for X3D chips specifically (and any other chips incorporating TSVs) is whether they retain the same sort of sealed backside coating or not. If the exposed TSVs of a die that has not been populated with a cache die on top - or if a stacked cache die exposes an uncoated edge around the periphery - cannot be coated with conductive metal due to the exposed TSVs, then those dies would be vulnerable to accelerated attack by Gallium.

 

[secrertqwerty10]

That's not a conformal coating or anything like that. It's a Kapton tape layer, which they've been using on pretty much all of their AMD CPU's with liquid metal. In the corner there's a bit of silver of the exposed frame, indicating that this is not a conformal coating or solder mask. There is indeed a small amount of foam bordering the edges of the exposed dies on the underside of the Kapton, and the small SMD's have a coating on them, but the reddish stuff is just their usual Kapton layer.

TL;DR they've been doing it exactly this way for a while now. Nothing new has been shown.

 

[NinoPino]

There is an error : ".,.applied to the protect the..."

 

[edzieba]

That's not a conformal coating or anything like that. It's a Kapton tape layer, which they've been using on pretty much all of their AMD CPU's with liquid metal. In the corner there's a bit of silver of the exposed frame, indicating that this is not a conformal coating or solder mask. There is indeed a small amount of foam bordering the edges of the exposed dies on the underside of the Kapton, and the small SMD's have a coating on them, but the reddish stuff is just their usual Kapton layer.

TL;DR they've been doing it exactly this way for a while now. Nothing new has been shown.

It's definitely not Kapton tape. Kapton tape does not conform to component Z-height as this substance does, even thin polyimide films are far too rigid to do that (and are thermosets, so will not soften with heating).