Patent Lawyer Blog
A federal district court in Idaho has denied Micron’s motion to disqualify the plaintiff’s infringement expert, even though the same expert served as Micron’s own testifying expert in an earlier DRAM patent case and reviewed internal schematics for many of the same products accused in the current suit.
In Advanced Memory Technologies, LLC v. Micron Technology, Inc., the district court held that Micron established a confidential relationship with the expert but failed to show it disclosed the kind of confidential information that warrants disqualification. The decision turns on the distinction between confidential technical information and confidential privileged information, and on the ten years that passed since the prior engagement.
AMT sued Micron for patent infringement in the Western District of Texas, alleging that Micron’s NAND flash memory and DRAM modules infringe AMT’s patents. The case was transferred in July 2026 to the District of Idaho, where Micron is headquartered. Micron then moved to disqualify AMT’s expert, Dr. Martin G. Walker, who had been Micron’s testifying expert from 2013 to 2016 in HSM Portfolio LLC v. Fujitsu, a patent case in Delaware involving some of Micron’s DRAM products.
The Court applied the two-part test from Hewlett-Packard Co. v. EMC Corp., under which courts should disqualify an expert if “(1) the adversary had a confidential relationship with the expert and (2) the adversary disclosed confidential information to the expert that is relevant to the current litigation.” Both factors must be met, the moving party bears the burden, and disqualification “is a drastic measure that courts should impose only hesitantly, reluctantly, and rarely.”
Micron easily satisfied the first prong. It engaged Dr. Walker through its outside counsel at Weil, Gotshal & Manges, paid him $475 an hour, and his own CV lists Micron as his client. In the earlier case, Dr. Walker studied internal schematics across more than thirty of Micron’s DRAM products, reviewed deposition testimony from Micron engineers, and submitted an expert report exceeding 1,000 numbered paragraphs, all under a written confidentiality agreement and protective order. Given the length of the engagement and the confidentiality agreement, the Court found it was reasonable for Micron to believe a confidential relationship existed.
The motion failed on the second prong. Confidential information in this context means information “of either particular significance or [that] which can be readily identified as either attorney work product or within the scope of the attorney-client privilege.” The Court noted that some courts have concluded that “[c]ommunication based upon technical information as opposed to legal advice is not considered privileged,” and that “[u]nlike attorney-client communications, discussions between parties or counsel and experts do not carry the presumption that confidential information was exchanged.”
Micron argued that the accused DRAM portfolio includes many of the same products Dr. Walker studied in the earlier case, and that he “will draw . . . on a decade-old reservoir of proprietary Micron knowledge that he acquired only because Micron entrusted him as its expert.” AMT responded that Micron had not identified any specific confidential information, and that what Micron disclosed was confidential technical information rather than confidential privileged information.
The Court found that distinction weighed against disqualification. Micron failed to show Dr. Walker was made privy to any aspect of its litigation strategy in the earlier case, except to say that his preparation “would have necessarily involved intimate coordination with Micron’s counsel.” The Court also observed that Micron is now represented by different counsel, which undermined the contention that Dr. Walker received privileged information about litigation strategy relevant to this action.
The Court acknowledged Micron’s point that confidential information is not limited to strategy, attorney-client communications, and work product, since the case law also covers information “of particular significance” or that is “specifically related to the product at issue in the litigation.” But even assuming a broader definition, the earlier case involved four different patents, none asserted here, directed to different technologies. The patents there covered buffers, latches, sense amplifiers, and logic circuits, while this case revolves around patents directed to booster circuits, charge pumps, and voltage regulators.
Although the Court did not need to reach the policy factors, it explained they would also weigh against disqualification. Micron argued that allowing Dr. Walker to serve as AMT’s expert would “send precisely the wrong signal” and suggest that “an expert may turn a former client’s confidences against it so long as the patents in the case bear different numbers.” The Court instead agreed with AMT that the remoteness of the engagement cut the other way. The engagement ended ten years ago, and Dr. Walker has worked on more than fifty matters since. The Court added that the parties’ own stipulated protective order requires disclosure of an expert’s prior consulting relationships for only the past five years, which “lends additional support to the proposition that ten years is sufficiently remote.” Dr. Walker also has specialized knowledge of the patents at issue, with a Ph.D. in electrical engineering from Stanford and over forty years of experience in integrated circuit design.
The decision is a useful reminder that a prior engagement with the other side, even one involving the same products, does not by itself disqualify an expert. The moving party must point to specific privileged or strategic disclosures, or confidential material tied to the technology actually in dispute. The passage of time matters too. A ten-year-old engagement, followed by decades of other work, will be hard to turn into a disqualification order.
Advanced Memory Technologies, LLC v. Micron Technology, Inc., Case No. 1:26-cv-00420-BLW (D. Idaho Aug. 31, 2026)
The authors of www.PatentLawyerBlog.com are patent trial lawyers at Jeffer Mangels & Mitchell LLP. For more information about this case, contact Stan Gibson at SGibson@Jeffer.com.