It may take a while to erase the black mark two San Francisco law firms — and their client, Qualcomm Inc. — received Monday courtesy of a San Diego federal judge, but the company and firms have all vowed to fight.

In a strongly worded 54-page ruling, San Diego federal Judge Rudi Brewster accused Qualcomm and its trial counsel of committing “gross litigation misconduct” by withholding crucial evidence in Qualcomm’s patent infringement case against Broadcom Corp. Though the judge did not identify the law firms by name, he specifically referred to Qualcomm’s representation up until the spring of this year, a time when the company was represented by Heller Ehrman and Day Casebeer Madrid & Batchelder.