How to introduce delay to a signal
simulate this circuit &ndash; Schematic created using CircuitLab



There is a tolerance on Vt+ and Vt- that shifts withtemperature that will make the delays asymmetric.

Also if the waveform is not repetitive, it will take 20% longer for the 1st edge.  

This is my approach if the delay tolerance is adequate.

Since the Schmitt trigger thresholds are 1/3 to 2/3  each delay is 2/3 of V+ which is very close to linear approximation of the RC exponential decay.