The country of origin of silicon metal-oxide-semiconductor field-effect transistors (“Si MOSFET”).

N355546
November 25, 2025
OT:RR:NC:N2:209
CATEGORY: Origin George Tuttle III Law Office of George R. Tuttle 3950 Civic Center Drive Ste 102 San Rafael, CA 94903 RE: The country of origin of silicon metal-oxide-semiconductor field-effect transistors (“Si MOSFET”). Dear Mr. Tuttle III: In your letter dated October 31, 2025, you requested a country of origin ruling on behalf of your client, iDEAL Semiconductor Devices Inc. The items concerned are referred to as silicon metal-oxide-semiconductor field-effect transistors (“Si MOSFET”), product no. iSI5M7R1S1C. The device is a silicon semiconductor die sourced and produced in the United States from raw or unprocessed wafers of Taiwanese origin. Production of the raw wafer (crystal growth, fabrication) will occur in Taiwan, with additional “front-end” die production steps occurring in the United Sates (epitaxial growth, photolithographic, physio-chemical processing). The die, in wafer form, are returned to Taiwan, where they undergo backgrinding/back metallization and chip probing. After fabrication, the die, in wafer form, are shipped to China for “back-end” manufacturing steps including wafer dicing and packaging of the individual die. The front-end processing that takes place in Taiwan and the United States are as follows: Wafer Fabrication within Taiwan Boule growth of Si crystal with As doping Slicing the boule into wafers Double-sided grinding Double-sided polishing Chemical-mechanical polishing (CMP) Creation of the MOSFET Circuitry within the United States Epitaxial growth using HTCVD Photolithography Photoresist, Exposure, and Developing

Etching and Ion Implantation The processing steps undertaken within the United States create individual die on the wafer, each containing a transistor. Each individual die manufactured in the United States that incorporates all of the intended electrical elements and their electrical interconnections. After completion of the front-end processing steps in the United States, the die in wafer form as shipped back to Taiwan where they undergo backgrinding, metallization and chip probing. The Taiwanese backgrinding, metallization and chip probing do not alter the end use of the transistor die. The backgrinding is used to thin the wafer as a prerequisite to the end packaging function. The metallization involves adding a very thin layer of metal to the backside of the wafer, which aids in the connection of the die to its final packaging. The back-end processing that takes place within China includes: Wafer mounting and dicing Plasma cleaning Die attachment Wire bonding Molding Plating Trim & form Testing/ laser marking/final visual inspection Packaging/ Shipping A complete explanation of the manufacturing steps taken in each country has been provided. When determining the country of origin for purposes of applying current trade remedies under Section 301 and additional duties, the substantial transformation analysis is applicable. See, e.g., Headquarters Ruling Letter H301619, dated November 6, 2018. The test for determining whether a substantial transformation will occur is whether an article emerges from a process with a new name, character, or use different from that possessed by the article prior to processing. See Texas Instruments Inc. v. United States, 681 F.2d 778 (C.C.P.A. 1982). This determination is based on the totality of the evidence. See National Hand Tool Corp. v. United States, 16 C.I.T. 308 (1992), aff’d, 989 F.2d 1201 (Fed. Cir. 1993). Based upon the facts presented, it is the opinion of this office that the front-end manufacturing process that take place in the United States is both meaningful and complex, resulting in the creation of individual die that incorporate all of the intended electrical elements and their electrical interconnections. Following front-end manufacturing steps in the United States, the wafers, which contain the die incorporating the complete transistor circuitry following front-end processing steps in the United States, do not undergo a substantial transformation as a result of that the backgrinding, metallization, and chip probing in Taiwan or by the back-end processing that take place in China. The product retains its identity as a silicon semiconductor die with a predetermined end use. Therefore, the country of origin of the finished silicon metal-oxide-semiconductor field-effect transistors (“Si MOSFET”) will be the United States. If a good is determined to be an article of U.S. origin, it is not subject to the country of origin marking requirements of 19 U.S.C. §1304. Whether an article may be marked with the phrase “Made in the USA” or similar words denoting U.S. origin, is an issue under the authority of the Federal Trade Commission (FTC). We suggest that you contact the FTC Division of Enforcement, 600 Pennsylvania Avenue, N.W., Washington, D.C. 20580 on the propriety of proposed markings indicating that an article is made in the U.S. The holding set forth above applies only to the specific factual situation and merchandise description as identified in the ruling request. This position is clearly set forth in Title 19, Code of Federal Regulations (CFR), Section 177.9(b)(1). This section states that a ruling letter is issued on the assumption that all of the information furnished in the ruling letter, whether directly, by reference, or by implication, is accurate and

complete in every material respect. In the event that the facts are modified in any way, or if the goods do not conform to these facts at time of importation, you should bring this to the attention of U.S. Customs and Border Protection (CBP) and submit a request for a new ruling in accordance with 19 CFR 177.2. Additionally, we note that the material facts described in the foregoing ruling may be subject to periodic verification by CBP. This ruling is being issued under the provisions of Part 177 of the Customs and Border Protection Regulations (19 C.F.R. 177). A copy of the ruling or the control number indicated above should be provided with the entry documents filed at the time this merchandise is imported. If you have any questions regarding the ruling, please contact National Import Specialist Steven Pollichino at [email protected].
Sincerely,
(for) Deborah Marinucci Designated Official Performing the Duties of the Division Director National Commodity Specialist Division