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HQ 952000




January 28, 1993

CLA-2 CO:R:C:M 952000 LTO

CATEGORY: CLASSIFICATION

TARIFF NO.: 9031.40.00; 9031.90.40

District Director
U.S. Customs Service
555 Battery Street
P.O. Box 2450
San Francisco, California 94126

RE: Protest No. 2809-92-100484; KLA Series 5000 Coherence Probe Metrology System; "optical"; HQ 084646; HQ 088231; 9012; EN 90.31; Add. U.S. Note 3 to Chapter 90; Corning Glass Works v. U.S.

Dear Sir:

This is in reference to Protest No. 2809-92-100484, dated March 10, 1992, which concerns the classification of the KLA Series 5000 Coherence Probe Metrology System (KLA 5000) under the Harmonized Tariff Schedule of the United States (HTSUS).

FACTS:

The article in question is the KLA 5000, which is an automated system that performs user-defined metrology measurements on multilayer integrated product wafers. The KLA 5000 consists of four major subsystems: (1) optics (interferometer microscope); (2) software; (3) electronic hardware (computer and hardware); and (4) mechanical system/wafer loading system (magazine with wafers and robotic arm).

The white light interferometer incorporated into the KLA 5000 contains an imaging lens, a beamsplitter, a microscope objective, a reference mirror and an illumination source. The interferometer splits incoherent light into two wave fronts. The zone where the paths interfere is called the coherence region. If both paths are equal, an interference signal is generated at a camera.

As the system scans the wafer's semiconductor substrate, - 2 -
interference is detected when the top of the feature passes through the coherence region. When the bottom of the surface passes through the coherence region, interference takes place at the camera for that area. The system combines the interference signal from all pixels. Image-processing algorithms determine the top and bottom widths, the pitch and feature height information.

The KLA 5000 has two metrology modes, linewidth registration and overlay. Measurement is performed by collecting both phase and amplitude information by the Coherent Probe Microscope (CPM), and then sending this information to the computer. The computer calculates and reports the dimensions and cross section of the wafer.

The KLA 5000 was entered under subheading 9031.80.00, HTSUS, which describes other measuring or checking instruments (parts of the KLA 5000 were entered under subheading 9031.90.60, HTSUS). The entry was liquidated under subheading 9031.40.00, HTSUS, which describes other optical measuring or checking instruments (the entry of parts of the KLA 5000 was liquidated under subheading 9031.90.40, HTSUS).

ISSUE:

Whether the KLA 5000 Coherence Probe Metrology System is an "optical" measuring or checking instrument under the HTSUS.

LAW AND ANALYSIS:

The General Rules of Interpretation (GRI's) to the HTSUS govern the classification of goods in the tariff schedule. GRI 1 states in pertinent part that "for legal purposes, classification shall be determined according to the terms of the headings and any relative section or chapter notes . . . ."

The KLA 5000 is classifiable under Heading 9031, HTSUS, which provides for "[m]easuring or checking instruments, appliances and machines, not specified or included elsewhere in this chapter; . . . parts and accessories thereof." This determination is not in dispute. However, the subheadings at issue are as follows:

9031.40.00 Other optical instruments and appliances

9031.80.00 Other instruments, appliances and machines - 3 -

The protestant argues that the KLA 5000 is not an optical instrument for the following reasons: (1) the KLA 5000 is functionally similar to the laser scanning microscope that this office determined was not an optical microscope in HQ 088231, dated March 8, 1991; (2) the KLA 5000 does not aid human vision; (3) the Harmonized Commodity Description and Coding System Explanatory Notes (EN) to Heading 9031, HTSUS, support the classification of the KLA 5000 as "non-optical"; and (4) the KLA 5000's optical components perform only a subsidiary role in the operation of the instrument.

In HQ 088231, dated March 8, 1991, this office classified a scanning laser microscope under subheading 9012.10.00, HTSUS, which provides for microscopes, other than optical microscopes. The protestant claims that the KLA 5000 is functionally similar to the scanning laser microscope, in that both are used to focus light and collect data for electronic processing, and, therefore, should be classified as "non-optical." This ruling, however, is inapplicable to the case at hand.

In HQ 088231, the issue was whether the microscope in question was an optical microscope, not whether the article was an optical measuring or checking instrument. In holding that the scanning laser microscope was not an optical microscope, we stated as follows:

The scanning laser microscope under consideration is neither a compound nor a simple optical microscope. It does not use microscope objectives to form and magnify images of the specimen. The images are formed when the collected data is processed electronically and displayed on a monitor. Although the microscope has optical elements, these elements are used to focus the laser beam onto the specimen. They are not the image forming optical elements which are the principal and most important optical components of "optical microscopes".

We then stated that the scanning laser microscope's "method of forming images is much more similar to that of an electron scanning microscope than an optical microscope," and held that the microscope was classifiable under subheading 9012.10.00, HTSUS. We did not hold, nor infer, that the scanning laser microscope was "non-optical." As such, HQ 088231 is not relevant to the classification of the KLA 5000.

The protestant claims that the KLA does not aid human vision, and therefore, cannot be considered an "optical
instrument." This restrictive interpretation limiting the terms "optical instruments" or "optical appliances" to instruments which aid human vision is based on outdated notions. Because of advancements in technology in the field of optics, many apparatus operate through the use of optical elements.

In HQ 084646, dated September 13, 1989, this office held "that an instrument is an optical instrument for classification purposes if the optics are required to process . . . the information in order to present it in usable form. This constitutes an aid or an enhancement of human vision." Further, EN 90.31, pg. 1533, states that subheading 9031.40, HTSUS, "covers not only instruments and appliances which provide a direct aid or enhancement to human vision, but also other instruments and apparatus which function through the use of optical elements or processes." Thus, the fact that the KLA 5000 does not provide a direct aid or enhancement to human vision does not take it beyond the scope of subheading 9031.40.00, HTSUS.

The protestant contends that the Explanatory Notes to Heading 9031, HTSUS, support the classification of the KLA 5000 as "non-optical," and that the optical components of the KLA 5000 perform only a subsidiary role in the operation of the instrument. Therefore, the protestant claims that the KLA 5000 cannot be classified as an optical instrument. We disagree.

EN 90.31, pg. 1532, lists a number of optical measuring and checking devices. This list, however, includes interferometers, which, it states, "are based on the principle of light interference, and comprise a standard optical flat and lenses with micrometric cross wires for measuring the interference bands." As stated above, the KLA 5000 incorporates a white light interferometer. Thus, the notes actually support the classification of the KLA 5000 under subheading 9031.40.00, HTSUS.

Finally, the protestant argues that the optical functions of the KLA 5000 are subsidiary to the remaining functions of the instrument, because these functions are not "at least co-equal" to the instrument's non-optical functions. See Corning Glass Works v. U.S., 82 Cust. Ct. 249, C.D. 4807 (1979). Additional U.S. Note 3 to Chapter 90 states that "[f]or the purposes of this chapter, the terms 'optical appliances' and 'optical instruments' refer only to those appliances and instruments which incorporate one or more optical elements, but do not include any appliances or instruments in which the incorporated optical element or elements are solely for viewing a scale or for some other subsidiary purpose."

While the optical components of the KLA 5000 make up only a
small portion of the total value of the system (9.25% of the total value), they are integral to the basic function of the apparatus, which is to perform user-defined metrology measurements on multi-layer integrated product wafers. Measurement is performed by collecting both phase and amplitude information by the Coherent Probe Microscope. A computer then calculates the information sent to it by the optical components of the KLA 5000.

In Corning Glass Works, the court stated that "[s]ince the Rota's [a machine for the optical inspection of drug-filled ampuls] sole purpose is optical inspection, its optical element is obviously at least coequal in function to the machine's nonoptical features." Id. at 257-258. The court further stated:

Although . . . an article cannot be classified as an optical instrument unless the dominant or primary use of the article lies in the employment of its optical features, it must be recognized that the optical element itself need not be the most important or dominant element of the instrument. As held in Ataka [U.S. v. Ataka America, Inc., 64 CCPA 60, C.A.D. 1184, 550 F.2d 33 (1977)], "the statutory distinction is between 'subsidiary' and not 'subsidiary' [and not whether the optical element is 'subsidiary' or 'dominant']." Id. at 258.

The optical components of the KLA 5000 are not used merely to obtain a readout or measurement of the results achieved independently by the nonoptical features of the machine. The primary function of the KLA 5000 is to perform user-defined metrology measurements. The optical elements of the KLA 5000 must be employed to perform this function. In fact, the optical components of the KLA 5000 are what sets the system apart from other optical measurement systems. In the literature provided by the protestant, it states:

The use of a white light incoherent source eliminates the ringing which degrades measurement integrity on narrow-band microscopes . . . . The combination of white light interferometer optical processing and computer extraction of phase and amplitude information also results in a narrower point-spread function than that inherent in other optical measurement techniques. A narrower point- spread function produces higher resolution for superior measurement performance.

Clearly, therefore, the function of the optical components is at least co-equal to that of the KLA 5000's non-optical - 6 -
functions. The optical components are not used to fulfill some "subsidiary" purpose. Therefore, it is our opinion that the KLA 5000 is classifiable as an optical measuring or checking instrument. Parts of the KLA 5000 will be classified accordingly.

HOLDING:

The KLA Series 5000 Coherence Probe Metrology System is classifiable under subheading 9031.40.00, HTSUS, which provides for "[m]easuring or checking instruments, appliances and machines, not specified or included elsewhere in this chapter . . . parts and accessories thereof . . . [o]ther optical instruments and appliances." Parts for the KLA 5000 are classifiable under subheading 9031.90.40, HTSUS. The corresponding rate of duty for articles of these subheadings is 10% ad valorem.

Accordingly, the protest should be denied in full. A copy of this decision should be attached to the Customs Form 19 and provided to the protestant as part of the notice of action on the protest.

Sincerely,

John Durant, Director

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