Searching for particular characters and return True or False

I am trying to adopt a code to find special characters in a string. Macro works if cell contains only one character in the code, but does not work if it is with other characters which are not in the code.

For instance, I am looking up semicolon sign anywhere in the string. If cell contains only one semicolon, it returns false as expected. However, if cell contains

abcd;

it returns true as not expected. How can I arrange it?

Function CharFinder(str As String) As Boolean
For I = 1 To Len(str)
 ch = Mid(str, I, 1)
 Select Case ch
  Case ",", ";", ".", "#", "*"
   CharFinder = False
  Case Else
   CharFinder = True
  Exit For
 End Select
Next
End Function

Thanks. It works like a charm.