Samsung has requested access to supply contracts between Apple and chipset maker Qualcomm that it hopes will serve as proof of patent infringement.
In documents filed to the US District Court in California this week, Samsung asked for contracts and correspondence related to the supply of the baseband chip used in several version of Apple's iPhone and iPad devices for mobile capabilities.
If the motion is granted, Samsung would be able to use the Qualcomm documents to bolster its attack on Apple in eight separate cases globally, including in Australia.
Samsung is alleging that Apple infringed its 3G patents making the iPhone and iPad.
Because Samsung licenses the patents to Qualcomm for use in baseband chips - which Apple uses in its devices - Apple maintains it is in license compliance.
However, Samsung hopes to derail this defence on grounds that Apple is not a "Qualcomm customer" as outlined in Samsung's agreement with the chipmaker.
"For Apple to be a Qualcomm Customer under the 2004 Samsung/Qualcomm license agreement, however, Apple must have purchased the chipsets at issue from Qualcomm and integrated them into the devices it sells to the public," Samsung argued in court documents.
The documents are expected to determine whether Apple is in fact a direct customer of Qualcomm - and potentially immune from Samsung's suits - or whether it purchased its chips through an intermediary.
As the patents allegedly infringed by Apple are vital to 3G communication standards under French jurisdiction, they must be licensed under fair, reasonable and non-discriminatory terms by Samsung.
Where Apple has claimed Samsung demanded exorbitant fees as high as a 2.4 percent levy on every chip installed in the iPhone 4S, legal counsel for the South Korean manufacturer argued in Australia and elsewhere that Apple did not act reasonably in negotiations.
Qualcomm has become a key player in the legal battle as Apple and Samsung tussle over access to their respective agreements with the chipset maker, as well as correspondence and the firmware used in the iPhone 4S, as provided by Qualcomm.
However, neither side has been forthcoming on the issue, with Apple's Australian lawyers characterising the Samsung/Qualcomm agreement submitted to the court in November last year as heavily redacted and "basically black".
Samsung's filing to the US District Court this week is also the second of its kind in the case, after Apple was granted access to documents relating to Qualcomm's license with Samsung in October last year.
Patent blogger Florian Mueller deemed Samsung's request "perfectly reasonable" but could be defeated if Apple is able to prove the supply chain between it and Qualcomm is of no relevance.
He said revelations of a "covenant not to sue" in Samsung's agreement with Qualcomm, rather than a straight license agreement, during recent hearings in France and Italy could also aid the South Korean manufacturer's line of attack.
"It can't be ruled out that the way the covenant not to sue is worded makes a distinction between customers supplied directly by Qualcomm and those who buy Qualcomm baseband chips from or through third parties," he said.