Qualcomm said in a lawsuit filed in California state court in San Diego on Wednesday that Apple used its commercial leverage to demand unprecedented access to the chipmaker's highly confidential software, including source code.
Apple declined to comment on the suit. The company started using Intel's broadband modem chips in the iPhone 7.
In its complaint, Qualcomm alleged that Apple was required under its contract to ensure that Apple engineers working with Qualcomm did not communicate details about Qualcomm chips to Apple engineers working on competing chips from Intel.
Qualcomm alleged that in July, Apple emailed Qualcomm to request "highly confidential" information about how its chips work on an unidentified wireless carrier's network. Apple copied an Intel engineer in the email for information, Qualcomm alleged.
In another instance, Qualcomm alleged that an Apple engineer working on a competing chip asked an Apple engineer working with Qualcomm to get technical information from Qualcomm.
Reuters reported earlier this week that Apple would drop Qualcomm's chips altogether from its iPhones and iPads beginning next year.
(Reporting by Sonam Rai in Bengaluru and Stephen Nellis in San Francisco; editing by Jeffrey Benkoe and Dan Grebler)