Apple, Google, Intel, Facebook, Yahoo, the Apache Software Foundation and the Electronic Frontiers Foundation (EFF) are amongst 11 organisations which have filed an amicus curae - friend of the court - brief in support of Microsoft's last ditch effort to overturn a US$290 million patent decision against it.
Microsoft Wednesday asked the US Supreme Court to consider the "standard of proof" rule applied in a patent case brought by Canadian software company i4i.
The Redmond giant lost an appeal in December last year, which may still force it to overhaul its Word program.
i4i's case relied on a patent for markup languages such Microsoft's XML, used to indicate how text should be displayed in an editing document.
According to Microsoft, i4i's patent, issued in 1998, was for a software product that had already been sold in the US over a year.
The Electronic Frontier Foundation said the patent examiner had failed to consider this fact when issuing rights over the invention.
The foundation had argued that current rules of evidence, which required "clear and convincing" evidence to invalidate a patent, unfairly burdened defendants, especially free and open source software patent holders.
"The standard undermines the traditional patent bargain between private patent owners and the public and threatens to impede innovation and the dissemination of knowledge," the EFF's Michael Barclay argued.
"Microsoft had proposed an instruction to the jury that Microsoft's burden of proof with regard to its defense of invalidity based on prior art that the examiner did not review during the prosecution of the patent-in-suit was by preponderance of the evidence," Microsoft's legal counsel wrote in its application.
According to Law.com, the "preponderance" standard is often referred to as "more likely than not" and represents a much lower standard required of defendants than is currently required.