Intel Adds 3D Decaps to Meteor Lake

Among the techniques available for improving performance and reducing power in processors, decoupling capacitors (decaps) don’t often rise to the top of the list. But companies are increasingly looking to decaps to ensure clean electrical operation and higher clock speeds.

Intel’s Meteor Lake processor, branded Core Ultra, advances decap technology with Intel’s first 3D decaps in the upper metal layers. The approach almost doubles the available capacitance per area.

Intel introduced decaps into their CPU products starting with the 22nm node. The structure and capacitance per area evolved steadily through the generations but has jumped significantly with the approach used on the Meteor Lake compute die, fabricated in the Intel 4 process with 18 metal layers and Intel’s first production use of extreme ultraviolet (EUV) lithography.

Graphcore has taken a similar tack, but it places its decaps on a separate wafer that’s then hybrid-bonded to the logic wafer. Those decaps achieve around 300 femtoFarads (fF)/mm2—which Intel’s Meteor Lake exceeds with 350 fF/mm2 on the compute die and 500 fF/mm2 on the base die.

We expect this approach to proliferate on future Intel chips where performance is critical. Intel’s chiplet approach allows more intense decoupling on the high-performance chiplets while less critical chiplets can maintain simpler structures.