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84.86 Machines and a paratus of a kind used solely or principally for the manufacture of semiconductor {oules or wafers, semiconductor devices, electronic integrated circuits or flat panel displays; machines and apparatus specified in note 9 (C) to this Chapter; parts and accessories. 8486.10 - Machines and apparatus for the manufacture of boules or wafers 8486.20 - Machines and apparatus for the manufacture of semiconductor devices or of electronic integrated circuits 8486.30 - Machines and apparatus for the manufacture of flat panel displays 8486.40 - Machines and apparatus specified in Note 9 (C) to this Chapter 8486.90 - Parts and accessories This heading covers machines and apparatus of a kind used solely or rincipally for the manufacture of semiconductor bodes or wafers, semiconductor devices, e ectronic integrated circuits or flat anel displays. However, this heading excludes machines and apparatus for measuring, chec 'ng, inspecting, chemical analysis, etc. (Chapter 90). f LI (A) MACHINES AND APPARATUS FOR THE MANUFACTURE OF BOULES OR WAFERS This group covers machines and apparatus for the manufacture of boules or wafers such as (1) One-melt furnaces for zone melting and refining of silicon rods, oxidation furnaces for oxidizing the surface of wafers and diffusion furnaces for doping the wafers with impurities. (2) Crystal growers and pullers for the production of extremely pure monocrystalline semiconductor boules from which wafers can be sliced. (3) Cr stal grinders, which 'nd the crystal boule to precise diameter required for wafers an to gnnd the flats on t e boule to indicate the conductivity type and resistivity of the crystal. B P (4) Wafer slicing saws, which slice wafers from a boule of monocrystalline semiconductor material. (5) Wafer grinders, lappers and polishers, which prepare the semiconductor wafer for the fabricabon process. This involves bringing the wafer within dimensional tolerances. Especially critical is the flatness of its surface. (6) Chemical mechanical polishers (CMP), which flatten and polish a wafer by combining chemical removal with mechanical bufing. (B) MACHINES AND APPARATUS FOR THE MANUFACTURE OF SEMICONDUCTOR DEVICES OR OF ELECTRONIC INTEGRATED CIRCUITS This group covers machines and apparatus for the manufacture of semiconductor devices or of electronic integrated circuits such as : (1) Film formation e uipment, which apply or produce various films on the surface of the wafer during the abrication process. These films serve as conductors, insulators and semiconductors on the finished device. They may include oxides and nitrides of the substrate surface, metals, and epitaxial layers. The processes and e uipments listed below are not necessarily limited to the generation of a particular type of fiR, 9L (a) Oxidation furnaces, which form a "film" of oxide on the wafer. The oxide is formed by the chemical reaction of the top molecular layers of the wafer with the applied oxygen or steam under heat. (b) Chemical Vapour Deposition CVD) equipment, which deposit various types of b films which are obtained b com ining the appropriate gases in a reactant chamber at elevated temperatures. d i s constitutes a thermochemical va or-phase reaction. Operations may take lace at atmospheric or low pressure (LP VD) and may use plasma enhancement ( ECVD). e (c) Physical Vapour Deposition (PVD) e ui ment, which deposit various types of films &r example : wh~chare obtained by vaporizing a soli!. (1) Evaporation equipment, in which the film is generated by heating the source material. (2) Sputtering equipment, in which the film is generated by bombarding the source material (target) with ions. (d) Molecular Beam E itaxy (MBE)equipment, which grow epitaxial layers on a heated monocrystalline su strate in an ultrah~ghvacuum using beams of molecules. The process is similar to PVD. 8' (2) Doping equipment, which introduce dopants into the wafer surface in order to modify the conductivity or other characteristics of a semiconductor layer such as : (a) Thermal diffusion equipment, in which the dopants are introduced into the surface of the wafer by the applicahon of gases under high temperatures. (b) Ion Im lantation, in which the dopants are "driven" into the crystal lattice structure of the s ace of the wafer in the form of a beam of accelerated ions. d (c) Annealing furnaces, which repair the crystal lattice structures of the wafer damaged by ion implantation. (3) Etching and stripping equipment for etching or cleaning surfaces of the wafers such as : (a) Wet etching e uipment, in which chemical etching materials are applied by spraying or immersion. !&ray etchers provide more uniform results than bath etchers, since they perform the operation on one wafer at a time. (b) Dry plasma etchin , in which etching materials are presented as gases within a plasma energy field, provifing an anisotropic etch profile. Dry-etchers use several d~fferent methods for creating gaseous plasma wh~ch removes thin film materials from semiconductor wafers. (c) Ion beam milling equipment, in which ionized gas atoms are accelerated toward the wafer surface. The impact results in the top layer being physically removed from the surface. (d) Strippers or ashers, using techniques similar to etching this apparatus removes the spent photoresist from the surface of the wafer after it has served its purpose as a " stencil ". This e uipment may also remove nitrides, oxides, and polysil~con, with an isotropic etch profi e. 'I (4) Lithogra hy equipment, which transfer the circuit designs to the photoresist-coated surface o the semiconductor wafer such as : F (a) Equipment for coating wafers with photoresist. These include the photoresist spinners which apply liquid photoresist evenly over the surface of the wafer. (b) Equi ment for exposing the photoresist coated wafer with the circuit design (or a part t ereof) : R (i) Using a mask or reticle and exposing the photoresist to light (generally ultraviolet) or, in some instances, X-rays : (a) Contact printers, where the mask or reticle is in contact with the wafer during exposure. r (b) Proximity aligners, which are similar to contact ali ers except actual contact does not take place between the mask or reticle and t e wafer. (c) Scannin aligners, which use rojection techniques to expose a continuously moving s it across the mask an wafer. (d) Step and repeat ali ners, which use a portion at a time. xposure can be or 1:1. Enhancements include the use % techniques to ex ose the wafer from the mas to the wafer P ,(ii) Direct write on wafer equipment. These apparatus operate with no mask or reticle. They use an automatic data processing machine-controlled "writing beam" such as an electron beam @-beam), ion beam or laser) to "draw" the circult design ectly on the photoresist coated wafer. 6, (5) Equipment for developing exposed wafers. These include chemical baths similar to those used in photographic laboratory applications. This heading also covers : (i) Centrifuges for spin-coating insulating substrate or wafers with photoresist. (ii) Screen printers for printing insulating substrate with etch-resisting ink. (iii) Laser scribing machines for dividing wafers into chips (dicing). (iv) Wafer dicing saws. (C) MACHINES AND APPARATUS FOR THE MANUFACTURE OF F l A T PANEL DISPLAYS This oup covers the fabrication of substrates into a flat panel. However, it does not cover the manu acme of glass or the assembly of printed circuit boards or other electronic components onto the flat panel. B This heading covers machines and apparatus for the manufacture of flat panel displays such as : ( 1 Apparatus for etching, developing, stripping or cleaning. (2) Apparatus for projection, drawing or plating circuit patterns. (3) Centrifugal spin dryers and other drying appliances. (4) Machines (spinners) designed to coat photographic emulsions. (5) Ion implanters for doping. (6) Furnaces, ovens and other equipment for diffusion, oxidation, annealing or rapid heating. (7) Chemical Vapour Deposition and Physical Vapour Deposition apparatus. (8) Machines for grinding and polishing. (9) Machines for sawing, scribing or scoring. (D) MACHINES AND APPARATUS SPECIFIED IN NOTE 9 (C) TO THIS CHAPTER This group covers machines and apparatus solely or principally of a kind used for : (1) the manufacture or repair of masks and reticles (e.g., appliances (photoplottexs) for the photogra hic production of photomasks and ion milling machines for the repair of masks and retic es); P (2) assembling semiconductor devices or electronic integrated circuits, e.g. : (a) Laser en raving machines for engraving the plastic casing of completed monolithic integrate circuits or discrete semiconductor components. B (b) Encapsulation equipment such as presses for making the plastic casings for chips by pressing plastic material around the chips. (c) Wire bonders for welding gold wires to the contact points of monolithic integrated circuits by ultrasonic or electrical compression welding. (d) Wafer bumping which is a process where connections are formed on an entire wafer before dicing, (3) Lifting, handling, loading or unloading of bodes, wafers, semiconductor devices, electronic integrated circuits and flat panel displays (e.g., automated material handling machines for trans ort, handling and storage of semiconductor wafers, wafer cassettes, wafer boxes and ot%er material for semiconductor devices). (E) PARTS AND ACCESSORIES to the general provisions regarding the classification of parts (see the General Note to Section XVI), the heading includes arts and accessories for the machines of this headin . Parts and accessories fa1 mg in this heading thus include, inter alia, work or tool holders an other special attachments whch are solely or principally used for the machines and apparatus of this heading. f P
1.- This Chapter does not cover : (a) Millstones, grindstones or other articles of Chapter 68; (b) Machinery or appliances (for example, pumps) of ceramic material and ceramic parts of machinery or appliances of any material (Chapter 69); (c) Laboratory glassware (heading 70.17); machinery, appliances or other articles for technical uses or parts thereof, of glass (heading 70.19 or 70.20); (d) Articles of heading 73.21 or 73.22 or similar articles of other base metals (Chapters 74 to 76 or 78 to 81); (e) Vacuum cleaners of heading 85.08; (f) Electro-mechanical domestic appliances of heading 85.09; digital cameras of heading 85.25; (g) Radiators for the articles of Section XVII; or (h) Hand-operated mechanical floor sweepers, not motorised (heading 96.03). 2.- Subject to the operation of Note 3 to Section XVI and subject to Note 11 to this Chapter, a machine or appliance which answers to a description in one or more of the headings 84.01 to 84.24, or heading 84.86 and at the same time to a description in one or more of the headings 84.25 to 84.80 is to be classified under the appropriate heading of the former group or under heading 84.86, as the case may be, and not the latter group. (A) Heading 84.19 does not, however, cover : (i) Germination plant, incubators or brooders (heading 84.36); (ii) Grain dampening machines (heading 84.37); (iii) Diffusing apparatus for sugar juice extraction (heading 84.38);