Thanks for the information from AmeenR. I was able to perform this fix to my car. Here is just a little write up to show you guys how to do it.
The main goal here is to get to that bar and apply something on the contact area to avoid metal rubbing.
Here is the procedure:
1. Remove the backseat's seatback. Fold the backseat down. At the bottom corners, take off 2 clips which attached the carpet to the seatback. Under that, you see the bolts that attaches the backseat to the hinge. Remove both bolts, and take out the seatback off the car.
2. Remove the backseat's buttom cushion. Release the seat from the button. There are 2 T-shaped release handles that you can pull. One at each side. Pull the cushion towards you and take out the cushion out of the car.
3. Now, we see the bar that you are going to remove. There are totally 10 bolts that hold the bar in place. Take all 10 bolts off using 10mm socket. Please realize that 2 bolts are different from the rest. Remember where these bolts came off from! At the back of the bar, there is a wire harness which attaches to the bar. Release the clips.
4. Now, you have a clean access to the bar. There are 10 bolts, so there are 10 contact points or more. Apply whatever you want to use to the area around the holes. I use 3M foam tape. I cut it into small pieces and just stick them to whatever I think there is contact area. Do that until you feel satified.
5. After you are done applying the foam tape or whatever. Install the bar and install everything that you took off during the procedure. Test drive and hope the noise is gone.
Any correction, let me know.
Cheers.