Sub Dispatcher()
Dim CptLig As Integer, CptChaine As Byte
Dim Chaines() As String
For CptLig = 1 To Range('A65536').End(xlUp).Row
Chaines = Split(Range('A' & CptLig), '_')
For CptChaine = 0 To UBound(Chaines)
Cells(CptLig, CptChaine + 1) = Chaines(CptChaine)
Next
Next
End Sub