I have a broken hard drive, apparently the problem is with the firmware.

I would like to extract the information from it. I tried to use the HDD Raw Copy Tool and it worked, it began extracting and outputing the information of the disk. I didn't finished doing because I was unsure of which format to use, and didn't want to waste time and space.

What format should I use to later recover the information from it? img or imgc?
After that, what program do I use to open it?

I understand all of the risks in doing it by myself. There is no vital and money-worth data in the disk, just family and personal stuff that I would like to get back.

Thanks in advance.

Before starting cloning, make sure that you can read actual data from the hard drive. Use disk editors to examine first sectors of the drive. I can't help with Raw Copy Tool, but it seems you are copying to image file and "imgc" is a compressed file.
If you don't know what it is, I suggest copy it to a physical drive, the same or higher capacity. Use free floppy/CD/USB bootable tools like R-Studio emergency disk or DMDE.