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Demystifying 丨 What is the process of soldering a new Intel processor


In addition to high performance, most attractive feature of ninth generation Intel Core processors is soldering process. So what is soldering? Today I will give you a brief analysis of what soldering is and what it is used for.

Demystifying 丨 What is the process of soldering a new Intel processor
01, processor core

Desktop processors require one more cover than mobile processors. The CPU without cover is shown in figure below. All cores are open and easily damaged. However, if it is in direct contact with heat sink, effect will be very good.

Demystifying 丨 What is the process of soldering a new Intel processor

Because laptops are relatively thin and light, unlike desktops, you can buy a heatsink to use, so desktop processors need to add a copper cover to CPU core.

Because copper cap and core are not connected to each other, there is a small gap in middle, so filler is needed to fill gap and fully connect core and top cap.

02, filler

Why is use of soldered Intel processors new? In fact, Intel has been using silicone grease instead of soldering as a filler for several years.

When using silicone grease, production process is very convenient. It is enough to apply silicone grease to core, and then glue top cover and glue it. However, peculiarity of silicone grease is that although it conducts heat well, it is not as good as metal and silicon. Grease dries out easily, so heat conduction won't work over time.

Demystifying 丨 What is the process of soldering a new Intel processor

Soldering refers to use of indium or group 4 elements as fillers, which have high thermal conductivity, and there is no need to worry that long-term use will reduce thermal conductivity. But soldering costs are high and process is complicated.

03. Soldering process

Soldering is more than just lubrication. The CPU top cover is copper, core is silicon, and indium is currently only material that can be soldered to both copper and silicon.

However, we can see that top cover of processor is made of silver, not pure copper. This is because pure copper oxidizes easily in air, so it must be protected with a metal layer, usually nickel-plated. This is also relatively common on heatsinks.

But nickel-plated top cap is not easy to bond with indium, so it must be plated with gold, so inside of top cap is plated with a layer of gold in addition to nickel plating, as in picture below it is gold.

Demystifying 丨 What is the process of soldering a new Intel processor

On a CPU core, core cannot come into contact with indium material, so core also needs to be plated with gold. Thus, indium material is effectively sandwiched between two gold-plated surfaces.

Before solder is placed between core and top cap, it must be heated to melt and flow into gap to make sure gap is completely filled, and then wait for it to solidify.

04. Why use soldering again

Since soldering is such a hassle, why use soldering process again? You should know that before 9th Gen Core, only Extreme and E5 and above series processors still used soldering, and after 2nd Gen Intel Core, they all opted for silicone grease.

It might have something to do with AMD. In 7th generation of processors and before, any generation of processors was better than FX series. Intel didn't care if temperature after overclocking was too high. emergence of AMD Ryzen, apart from rush of Intel After launch of eighth generation, it was immediately upgraded to ninth generation, and ninth generation i7 and ninth generation i9 are performance monsters, and heat dissipation requirements are much higher Therefore, Intel has to use reverse soldering.

05. Can solder be opened?

We all know that there is a saying about opening lid and replacing liquid gold. Intel processors that use silicone grease can use lid open operation to replace liquid gold for better heat dissipation, but this should be understood. here is that although thermal conductivity of liquid gold and solder welding are relatively close, but it cannot be called soldering after replacing liquid gold, soldering is different from liquid gold.

A soldered processor can also be opened, but this is more troublesome and comes in two types. Soldering can be divided into hard soldering and soft soldering. We mentioned above that materials like indium need to be heated to fit into gap between top cover and processor core and then wait for it to solidify, so it also needs to be heated to open cover. If temperature to be heated reaches 450 degrees Celsius, then it is hard soldering. This heat dissipation effect is very good, but if you open cover directly, processor will be scrapped.

Demystifying 丨 What is the process of soldering a new Intel processor

And if heating temperature is low or lid can be opened directly without heating, then this is soldering, which actually looks like liquid gold. However, it is now being reported that 9th Gen Core seems to be able to open lid directly without heating, indicating that 9th Gen uses soldering.