echo $PATH | grep "\/usr\/ucb[:$]" is not working using sh-posix

The problem is very simle.
I want to check '/usr/ucb' is in the PATH environment variable.
If i simply grep '/usr/ucb' i might got wrong result eg '/usr/ucb/bin'.
After the path an end of line or colon character should be.

In other words: in range expression how can i use special character like $.

Thanks in advance
FPETER