In terms of pure-play, there are relatively little companies that are 100% copper production. If you're looking for a company that has a heavy amount of copper exposure though, it would be something like Lundin Mining, it trades under the ticker LUN. I believe at the time of me writing this, over 70% of its total production is copper. You could look to a company like Ero Copper as well, which trades under the ticker ERO.
Now on that note, would I necessarily recommend any of them? I'm not sure really, it all depends on your overall risk profile. What I will say is these companies aren't really long term holds. They need to be bought into and exited out of based on pricing cycles. If you look at a chart of Ero Copper though, it seems to break that rule and has put up outstanding returns. But generally, when you're buying a company that is solely focused, or at least really closed to solely focused, on a single commodity, it's share price and cash flow tends to track that commodity.
This is why it has been so hard to make any money off of pure-play miners over the years. We see the same struggles in gold, oil, silver, etc, besides a select few that do break out from the pack.
But, to get you started in terms of research, Lundin and Ero are likely to be your strongest options in terms of producers with a high percentage of production in copper.