I used other option too but still the same problem.
I also search for the solution online but I can’t find it.
Does anyone know how to fix this problem?
In edit or pose mode, select the IK target bone, then look on properties/bone/deform. Uncheck the deform box. Now it won’t be considered for the armature modifier, and it won’t be considered for weights with autoweights.
It would be wise to recalculate any autoweights after disabling deform on any bones, although here, it’ll probably be okay even without recalculation.