By: Adrian (a.delete@this.acm.org), June 13, 2022 5:27 am
Room: Moderated Discussions
Sean M (sean.delete@this.none.com) on June 13, 2022 3:28 am wrote:
> Thank you for your excellent article. In Figure 3, at a frequency of 3.3 GHz, the normalized power of
> Intel 4 with 8 Vt is 61% less than Intel 7 (1.75 vs 4.5). The frequency at a nominalized power of 3.75
> is 12.3% higher for Intel 4 with 8 Vt compared to Intel 7 (3.65 GHz vs 3.25 GHz). Based on the right side
> of Figure 3, it looks like Intel 4 is better at reducing power than increasing clock frequency.
>
> On the left side of Figure 3, the improvement for Intel 4 is 40% less power or 21.5% higher frequency.
> Do you have an intuitive way of understanding why the newer process has a larger power savings but
> a smaller frequency increase at a high supply voltage compared to a low supply voltage?
>
> Table 2 shows Intel 4 has pairs of metal layers for M5 to M14 with the same pitch,
> but M1 to M4 don’t follow that pattern. What do you think is the rationale for
> having a pitch of 50nm for M1 and M3 while the pitch is 45nm for M2 and M4?
About the pitch of the metal layers, most metal layer are used in pairs for traces at 2 orthogonal directions.
Most layer pairs have the same pitch, except M1-M2 and M3-M4, where each pair has 50 nm in one direction and 45 nm in the orthogonal direction.
In this case the difference arises because one direction is parallel with the fins and the other is perpendicular on the fins. The 90% pitch ratio has resulted from the optimization of the layout of simple gates. An example layout is shown in one of the slides, but without all relevant details.
For layers higher in the stack, which do not connect directly the transistors, but only lower layers, the relationship with the fins does not matter any more, so the 2 orthogonal directions are equivalent and they use the same pitch.
> Thank you for your excellent article. In Figure 3, at a frequency of 3.3 GHz, the normalized power of
> Intel 4 with 8 Vt is 61% less than Intel 7 (1.75 vs 4.5). The frequency at a nominalized power of 3.75
> is 12.3% higher for Intel 4 with 8 Vt compared to Intel 7 (3.65 GHz vs 3.25 GHz). Based on the right side
> of Figure 3, it looks like Intel 4 is better at reducing power than increasing clock frequency.
>
> On the left side of Figure 3, the improvement for Intel 4 is 40% less power or 21.5% higher frequency.
> Do you have an intuitive way of understanding why the newer process has a larger power savings but
> a smaller frequency increase at a high supply voltage compared to a low supply voltage?
>
> Table 2 shows Intel 4 has pairs of metal layers for M5 to M14 with the same pitch,
> but M1 to M4 don’t follow that pattern. What do you think is the rationale for
> having a pitch of 50nm for M1 and M3 while the pitch is 45nm for M2 and M4?
About the pitch of the metal layers, most metal layer are used in pairs for traces at 2 orthogonal directions.
Most layer pairs have the same pitch, except M1-M2 and M3-M4, where each pair has 50 nm in one direction and 45 nm in the orthogonal direction.
In this case the difference arises because one direction is parallel with the fins and the other is perpendicular on the fins. The 90% pitch ratio has resulted from the optimization of the layout of simple gates. An example layout is shown in one of the slides, but without all relevant details.
For layers higher in the stack, which do not connect directly the transistors, but only lower layers, the relationship with the fins does not matter any more, so the 2 orthogonal directions are equivalent and they use the same pitch.
