Let clarify this point pinoy.
R increase when T increase and vice versa in Metals (All Conductors).
R decrease when T increase and vice versa in semiconductors.
Added after 15 minutes:
If only we consider the signal:
Signal in a Metal Wire: T increase , R increase and vc. vs so Delays increase
Signal in a Semiconductor: T inc, R dec and vc vs so Delays dec.
We have to not ignore the impact of temperature on Transistors which controle and generate signal.