Memories

85.42 - Electronic integrated circuits. - Electronic integrated circuits : 8542.31 - - Processors and controllers, whether or not combined with memories, converters, logic circuits, amplifiers, clock and timing circuits, or other circuits - - Memories 8542.33 - - Amplifiers 8542.39 - - Other 8542.90 - Parts 8542.32 The articles of this heading are defined in Note 8 (b) to the Chapter. Electronic integrated circuits are devices having a high passive and active element or component density, which are regarded as single units (see Explanatory Note to heading 85.34, first paragraph concerning elements or components to be regarded as assive" or "active"). However, electronic circuits containing only passive elements are exclude &om this heading. &3 Unlike electronic integrated circuits, discrete components ma have a single active electrical function (semiconductor devices defined by Note 8 (a) to hapter 85) or a single passive electrical function (resistors, capacitors, inductances, etc.). Discrete components are indxvisible and are the basic electronic construction components in a system. However, components consisting of several electric circuit elements and having multiple electrical functions, such as integrated circuits, are not considered as discrete components. Electronic integrated circuits include memories (e.g., DRAMS, SRAMs, PROMS, EPROMS, EEPROMS (or E'PROMS)), microcontrollers, control circuits, logic circuits, gate arrays, interface circuits, etc. Electronic integrated circuits include : (I) Monolithic integrated circuits. These are microcircuits in which the circuit elements (diodes, transistors, resistors, capacitors, inductances, etc.) are created in the mass essentially) and on the surface of a semiconductor material (doped silicon, for exarnp e) and are therefore inseparabl associated. Monolithic integrated circuits may be digital, linear (analogue) or digitaz analogue. I Monolithic integrated circuits may be presented : (i) Mounted, i.e., with their terminals or leads, whether or not encased in ceramic, metal or plastics. The casings may be cylindrical, in the form of parallelepipeds, etc. (ii) Unmounted, i.e., as chips, usually rectangular, witb sides generally measuring a few millimetres. (iii) In the form of undiced wafers (i.e., not yet cut into chips). Monolithic integrated circuits include (i) Metal oxide semiconductors (MOS technology). (ii) Circuits obtained by bipolar technology. (iii) Circuits obtained by a combination of bipolar and MOS technologies (BIMOS technology). (11) Hybrid integrated circuits. These are microcircuits built u on an insulating substrate on which a thin or thick film circuit has been formed. T is process allows certain passive elements (resistors, ca acitors, inductances, etc.) to be produced at the same time. However, to become a hy rid integrated circuit of this heading, semiconductors must be incorporated and mounted on the surface, either in the form of chips, whether or not encased, or as encased semiconductors (e.g., in specially desi ed miniature casin s). Hybrid integrated circuits may also contain separately produce passive elements w ich are incorporated into the basic film circuit in the same way as the semiconductors. Usually these passive elements are components such as capacitors, resistors or inductors in the form of chps. !i g 'f= i Substrates made up of several la ers, generally ceramic, heat-bonded together to form a compact assembl are to be t en to form a single substrate within the meaning of Note 8 @) (ii) to t%s Chapter. I The components forming a hybrid integrated circuit must be combined to all intents and purposes indivisibly, i-e., though some of the elements could theoretically be removed and r laced, this would be a long and delicate task which would be uneconomic under norma manufacturing conditions. "P (m)Multichip integrated circuits. These consist of two or more interconnected monolithic integrated circuits combined to all intents and p oses indivisibly, whether or not on one or more insulating substrates, with or without lea arnes, but with no other active or passive circuit elements. % Multichip integrated circuits generally come in the following configurations : - Two or more monolithic integrated circuits mounted side by side; - - Two or more monolithic integrated circuits stacked one upon the other; Combinations of the configurations above consisting of three or more monolithic integrated circuits. These monolithic inte ated circuits are combined and interconnected into a single bod and may be package through encapsulation or otherwise. They are combined to intents and urposes indivisibly, i.e., though some of the elements could theoretically be removed an replaced, this would be a long and delicate task which would be uneconomic under normal manufacturing conditions. ! f d Insulating substrates of the multichip integrated circuits ma incorporate electrically conductive regions. These regions may be composed of speciTic materials or formed in s ecific sha es to provide passive functtons by means other than discrete circuit elements. &ere congctive regions are present in the substrate, they are typically relied upon as a means by which the monolithtc integrated circuits are interconnected. These substrates may also be referred to as "interposers" or "spacers" when placed above the bottom-most chip or die. Monolithic inte~atedcircuits are interconnected by a variety of means, such as adhesives, wire bonds, or ' flip chip" technology. The heading excludes film circuits consisting solely of passive elements (heading 85.34). This heading does not include solid-state non-volatile stora e devices, "smart cards" and other media for the recording of sound or of other phenomena (see heading fi5.23 and Note 4 to this chapter). I Except for the combinations (to all intents and p oses indivisible) referred to in Parts II) and (III) above concerning hybrid integrated circuits and m#chip integrated circuits, the heading a so excludes assemblies formed by : (a) Mounting one or more discrete components on a support formed, for example, by a printed circuit; (b) Adding one or more other devices, such as diodes, transformers, or resistors to an eIectronic microcircuit; or (c) Combinations of discrete components or combinations of electronic microcircuits other than multichip-type integrated circuits. Such assemblies are classified as follows : (i) Assemblies which constitute a complete machine or appliance (or one classified as complete), in the heading appropriate to the machine or appliance; (ii) Other assemblies, in accordance with the provisions for the classification of machine parts (Notes 2 (b) and 2 (c) to Section XVI, in particular). This is the case, in particular, for certain electronic memory modules (e.g., SIMMs (Single In-line Memory Modules) and DIMMs ual In-line Memo Modules)). Those modules are to be classified by application of Note 2 to Section (See the 0eneral%xplanstoW~ o t to e h s Chapter). PARTS h Sub'ect to the general provisions regarding the classification of parts see the General ~xpLatory~ o t to e Section XVI), parts of thc goods of this heading are classi led here.