United States v. Yu

Court of Appeals for the First Circuit·Decided December 11, 2025·No. 24-1325·Published

Opinion

United States Court of Appeals For the First Circuit

Nos. 23-1585 24-1325

UNITED STATES,

Appellee,

v.

HAOYANG YU,

Defendant, Appellant.

APPEALS FROM THE UNITED STATES DISTRICT COURT FOR THE DISTRICT OF MASSACHUSETTS

[Hon. William G. Young, U.S. District Judge]

Before

Montecalvo, Lipez, and Aframe, Circuit Judges.

William W. Fick, with whom Daniel N. Marx, Amy Barsky, and Fick & Marx LLP were on brief, for appellant.

Karen Lisa Eisenstadt, Assistant United States Attorney, with whom Leah B. Foley, United States Attorney, was on brief, for appellee.

December 11, 2025

MONTECALVO, Circuit Judge. Haoyang Yu worked for Analog Devices, Inc. ("ADI"), a company that designs and produces microchips. While employed there, Yu downloaded ADI's proprietary information and held onto it after leaving the company. He soon started selling microchips that were similar to ADI's. A grand jury indicted Yu on twenty-one counts, spanning possession of stolen trade secrets, wire fraud, illegal exports of controlled technology to Taiwan, visa fraud, and unlawful procurement of citizenship. At trial, a jury convicted Yu on just the first count: unlawful possession of a trade secret in violation of 18 U.S.C. § 1832(a)(3). Yu now appeals, challenging the sufficiency of the evidence as to particular elements of the charge. He also claims unconstitutional selective enforcement and prosecution, alleging that, because he is from China, he was investigated and prosecuted much more harshly than someone who is not ethnically Chinese would have been.

For the following reasons, we affirm.

I. Factual Background

We recount the facts relevant to Yu's sufficiency challenge in the light most favorable to the prosecution. See United States v. Díaz-Rosado, 857 F.3d 116, 117 (1st Cir. 2017). We provide a neutral summary of the facts relevant to his other claims. See id.

Because the jury ultimately convicted Yu on only one count -- possession of a stolen trade secret, specifically, "[t]he design layout and GDS file for the HMC1022A microchip" -- we focus on the facts relevant to that charge.1 We refer to this electronic file that Yu was accused of possessing as the "charged file."

We begin with relevant background about ADI and its work.

ADI creates microchips, which are devices that process and store information and help make electronic appliances work. As relevant to this case, ADI develops radio frequency and microwave amplifier microchips (also called "monolithic microwave integrated circuits" or "MMICs") that allow electronic devices to broadcast and send signals over the air. MMICs are tiny; comparing them to the tip of a pencil, they can measure approximately one pencil tip long and two pencil tips wide. ADI designs MMICs for use in infrastructure -- for example, airplanes and cell phone towers -- as opposed to consumer goods. ADI has customers in the cell phone, auto, aerospace, and defense industries. ADI's MMICs have military uses, such as in satellites and radar. ADI designs the microchips and uses Win Semiconductor ("Win"), a company based in Taiwan, to manufacture them.

In 2014, ADI acquired another microchip company called Hittite Microwave Corporation ("Hittite"). Before the

1A GDS file is the type of computer file used to convey a design layout.

acquisition, Hittite manufactured some of its MMIC designs at Win and some with another manufacturer. Each microchip manufacturer has its own particular set of manufacturing technologies, which makes it difficult for designers to switch manufacturers. But after the acquisition, ADI began the painstaking process of translating Hittite's non-Win designs into designs that could be manufactured by Win.

Designing a MMIC is an iterative process. First, the designer creates a three-dimensional "schematic" for how the MMIC should operate, involving potentially thousands of mathematical formulas to model how various components work together. This process can take an experienced designer several weeks. Next, the designer uses a computer to run simulations to test how well the schematic works. The designer runs thousands of simulations to refine the schematic.

At the next stage, the designer creates the layout, which is a diagram that describes precisely how the components of the MMIC fit together and contains all the information needed to manufacture the MMIC. The designer then returns to the schematic and simulation stages and refines the design layout. The overall process, from starting the first schematic to creating a design layout ready to be manufactured and tested, can take three to six months.

When the designer thinks the design layout is ready, ADI creates what is called a GDS file and sends it to Win to manufacture a prototype. Manufacturing a MMIC prototype typically takes Win around six weeks and costs ADI $35,000 to $50,000. Win manufactures thousands of the prototype MMIC, which ADI then tests hundreds of times on equipment that costs hundreds of thousands of dollars. The first prototype is almost never ready for the market. Instead, the designer will return to the design phase to further refine the design, creating new prototypes as needed until the design layout is finalized and the MMIC is ready to go to market. A typical MMIC sells for around $200.

The translation process, which ADI used to recreate Hittite's existing MMICs into design layouts that Win could manufacture, involves the same iterative design process. But translations can take even more time and effort because the finished product must exactly mirror the existing product. In other words, the translation should not be better or worse; it must be the same in every way. To track these translated MMICs, ADI named the finished product using "HMC" (to denote Hittite), followed by Hittite's identification number for the original MMIC, and appended an "A" to it to denote that it was ADI's translation rather than the original.

Yu had recently begun working at Hittite at the time of its acquisition in 2014. He became an ADI employee in the

acquisition. Yu had previously worked on microchip products geared towards consumer applications, but at ADI, he transitioned to microchips for industrial use and learned the relevant skillset to work on translating Hittite's MMIC designs.

Yu signed confidentiality agreements with ADI, which defined "[c]onfidential [i]nformation" as including "all information acquired by [Yu] from ADI . . . that relates to the past, present[,] or potential . . . products . . . of ADI." Yu agreed that he would not disclose this confidential information to any third parties, would not "make use" of such information "for [his] own purposes . . . under any circumstances during or after the term of [his] employment," and that he would return all such information to ADI at the end of his employment.

In approximately mid-2016, Yu began saving copies of some of ADI's GDS files to his personal computer. He changed the names of some of these files to the names of Pokémon characters. ADI's file called "K8600_TOP.gds" contained multiple MMIC design layouts, including the HMC1022A prototype (the charged file). When Yu copied this file, he renamed it as "Kids8600.jpg" as though it were a photograph of his children. However, one could only open the file by changing the file extension from ".jpg" to ".gds."

In January 2017, Yu emailed Win to ask whether it would work with a small business. Win replied that it would, but that it would likely require payment upfront and that it would need a

non-disclosure agreement. Yu agreed to these terms. Yu also began reaching out to potential customers about working with a new MMIC design company.

In March 2017, Yu registered a new company called Tricon MMIC, LLC ("Tricon") under his wife's name, Yanzhi Chen. Tricon's website advertised its MMICs as potential substitutes for or improved versions of ADI's MMICs, including the HMC1022.

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