Global Standards for the Microelectronics Industry
See "write enable".References:
A slice or flat disk, either of semiconductor material or of such a material deposited on a substrate, in which circuits or devices are simultaneously processed and subsequently separated into chips if there is more than one device.References:
A package whose size is generally equal to the size of the semiconductor device it contains and that is formed by processing on a complete wafer rather than on an individual device.
NOTE 1 Because of the wafer-level processing, the size of a wafer-level package may be defined by finer dimensions and tighter tolerances than those for a similar non-wafer-level package.
NOTE 2 The package size will change with changes in the size of the die.References:
A signal indicating that the device addressed by the central processing unit has not yet completed its data transfer. (Ref. IEC 824.)References:
water vapor transmission rate (WVTR)
A measure of the permeability of plastic film or metallized plastic film material to moisture.References:
See "write enable".References:
An imperfection or deviation from the designed construction that affects reliability.References:
wedge bond; stitch bond
The adhesion or weld of a thin wire, usually aluminum, to a package bonding surface, usually a plated leadframe post or finger, using an ultrasonic wire-bonding process. The wedge bond includes the compressed (ultrasonically bonded) area of the wire and the underlying bonding surface. For bonding to an aluminum alloy die bond pad, there is no wedge bond-bond pad intermetallic because the two materials are of the same composition; the two materials are recrystallized together by the ultrasonic energy of the welding process.References:
The formation of a relatively uniform, smooth, unbroken, and adherent film of solder to a basis metal. (Ref. IPC‑T‑50.)References:
Wheatstone bridgeA 4-arm bridge forming a diamond, all of whose arms are predominantly resistive, with three resistors of known values in three of the arms and the unknown resistor in the fourth.
NOTE 1 A voltage source, e.g., a battery, is connected across two opposite points of the diamond and a current-detecting instrument (e.g., a galvanometer) is connected across the other two points. The values of one or two of the known resistors are varied until no current flows through the galvanometer. The bridge is then balanced and the value of the unknown resistor can be calculated in terms of the other three.
NOTE 2 A method using the Wheatstone bridge for monitoring resistance of solder bumps in electromigration tests has greater sensitivity to resistance change than other methods. Net resistance changes due to electromigration of only the solder bumps, excluding the Al or Cu traces, can be deduced by this method.References: JEP154, 1/08
A spontaneous columnar or cylindrical filament, usually of monocrystalline metal, emanating from the surface of a finish.
NOTE Whiskers are not to be confused with dendrites, which are fern-like growths on the surface of a material, formed as a result of electromigration of an ionic species or during solidification.References:
The number of whiskers per unit area on a single lead or coupon area.References:
Measurable changes in whisker length and/or whisker density after exposure to a whisker test condition for a certain duration or number of cycles.References:
The straight-line distance from the point of emergence of the whisker to the most distant point on the whisker.References:
whisker test coupon
A piece of metal of specified size and shape that is plated or dipped with a tin finish for the purpose of measuring the propensity for whisker formation and growth.References:
width (of a data path)
The number of data lines used in parallel transmission.
NOTE For digital data, width is usually expressed in bits, bytes, or words.References:
A hole formed by etching through an oxide or insulating layer on a semiconductor for the purpose of diffusion into or deposition onto a selected area of the semiconductor.References:
Work in progress or work in process.References:
The total amount of interconnect of a net (specified in units of either length or capacitance).References:
A character string or a binary element string that it is convenient to consider as an entity. (Adapted from ANSI X3.172.)
NOTE For memories, it is common practice to use the term "word" generically for any number of bits that occupy a single address location.References: