The country of origin of a silicon wafer

N359887 March 31, 2026 OT:RR:NC:N2:209 CATEGORY: Origin Aaron Marx Crowell & Moring, LLP 1001 Pennsylvania Ave NW Washington, FL 20004 RE: The country of origin of a silicon wafer Dear Mr. Marx: In your letter dated March 19, 2026, you requested a country of origin ruling on silicon epitaxial wafers, on behalf of your client Okmetic Inc. The item concerned is a silicon epitaxial wafer (product # 827906), that will be used to manufacture metal oxide semiconductor field effect transistors (“MOSFET”). The wafer will be manufactured in Finland, and an epitaxial layer will be added in China. A transistor is a miniature semiconductor that regulates or controls electrical currents and can act as a switch or gate. The substrate of a MOSFET is the foundational layer that supports the transistor structure, including the source, gate, and drain terminals. The material properties of the substrate can be used to control the threshold voltage and the electric field within the transistor. Substrate resistivity is one of the key parameters in developing a specific resistance for the end use product. The dopant concentration within the substrate is tightly controlled. Both the wafer and the epitaxial layer are doped to provide a negative attribute to the commodity. The addition of a negatively doped epitaxial layer to a negatively doped substrate does not change the electrical attributes of the wafer. The epitaxial wafer does not incorporate a positive/negative (p/n) junction. The p/n junction is formed during the downstream fabrication of the actual transistor. The substrate undergoes a complex production process that sets the foundation for the wafer’s end use, character, and essential function. The deposition of the epitaxial layer merely adds to the substrate’s inherent properties. (see N345524). In Finland, the substrate then undergoes the following manufacturing process: Crystal Growth Ingot Cropping Ingot Grinding Water Slicing and Cleaning Edge Grinding Lapping and Cleaning Acid Etching Visual Inspection Cleaning Polybacking Low Temperature Oxide Low Temperature Oxide Edge Strip Visual Inspection Front Side Polishing and Cleaning Final Sorting Laser Marking Final Section Cleaning and Inspection Packing The epitaxial layer manufacturing process in China includes the following: Incoming quality control (“IQC”) Material access Clean and Inspection Epitaxial Processing Testing Visual Inspection Cleaning Surface Flatness Test Particle Surf Scanning Packaging Warehousing Shipping 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). Additionally, Section 304 of the Tariff Act of 1930, as amended (19 U.S.C. 1304), provides that unless excepted, every article of foreign origin imported into the United States shall be marked in a conspicuous place as legibly, indelibly, and permanently as the nature of the article (or its container) will permit, in such a manner as to indicate to the ultimate purchaser in the United States, the English name of the country of origin of the article. Congressional intent in enacting 19 U.S.C. 1304 was “that the ultimate purchaser should be able to know by an inspection of the marking on the imported goods the country of which the goods is the product. The evident purpose is to mark the goods so that at the time of purchase the ultimate purchaser may, by knowing where the goods were produced, be able to buy or refuse to buy them, if such marking should influence his will.” See United States v. Friedlaender & Co., 27 C.C.P.A. 297, 302 (1940). Part 134 of the U.S. Customs and Border Protection (“CBP”) Regulations (19 CFR 134) implements the country of origin marking requirements and exceptions of 19 U.S.C. 1304. Section 134.1(b), CBP Regulations (19 CFR 134.1(b)), defines “country of origin” as the country of manufacture, production, or growth of any article of foreign origin entering the United States. Further work or material added to an article in another country must effect a substantial transformation in order to render such other country the “country of origin” within the meaning of the marking laws and regulations. Based upon the facts presented, it is the opinion of this office that the processing that takes place within F inland is both meaningful and complex, resulting in the creation of a negatively doped silicon wafer. The character of this particular wafer is imparted by the material used to manufacture the wafer (silicon), the manufacturing specifications, and the type of dopant used to provide a particular electrical attribute (positive or negative). This wafer would be considered the dominant component. It does not undergo a substantial transformation as a result of the manufacturing process that takes place within China. The wafer retains its identity and predetermined end use. The electrical attributes are not substantially changed as a result of the Chinese processing. Therefore, the country of origin of the silicon epitaxial wafer (product # 827906), will be Finland for marking purposes and for the purposes of applying current trade remedies and additional duties. 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 steven.pollichino@cbp.dhs.gov. Sincerely, (for) James Forkan Designated Official Performing the Duties of the Division Director National Commodity Specialist Division