Scott Phillips filed legal docs and said he wants her to pay spousal support. That could be a hefty payout for Scott if he gets it -- Julie is reportedly making $500k per episode on "Modern Family" for seasons 9 and 10.

In the docs -- obtained by TMZ -- Scott said he also wants joint physical and legal custody of their 3 kids. But the biggy here is spousal support.

The "Modern Family" star is raking in tons of dough off the show, and there's also endorsement deals, including from Neutrogena. Forbes estimated she made about $10 million in 2016, alone.

TMZ broke the story ... Julie called it quits with her husband of 13 years when she filed for divorce back in February. As we reported ... their relationship had been on the rocks for some time.