Glossary

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Al/NiV/Cu: Combination of thin film conductor layers that are sputtered and then etched to form the UBM pads in FlipChip's SFC, Repassivation, UltraCSP, and Polymer Collar WLP flows. Also forms the redistribution runners in the UltraCSP flow. Also known as one of the combinations of metals used to form the Under-Bump-Metallurgy (UBM).
Array: A pattern of columns and rows. Used to describe bumps that are evenly spaced in rows and columns all across the die surface and not just near the edges.
Array Pattern: Number of rows and columns in a matrix-designed layout of solder balls. Can be a fully formed array or may be partially depopulated, with the absence of bumps toward the center of the array.
Ball Diameter: Diameter of the pre-formed solder sphere used in Wafer Level Packaging. Typical ball diameters are 300, 350, 400, and 500µm.
BCB: (Benzocyclobutene) Dielectric coating that provides an additional passivation layer on top of the IC passivation for Repassivation, Redistribution, UltraCSP, and Polymer Collar WLP designs.
BCB1 Opening (Via): Opening in the first layer of BCB where IC aluminum pads will be re-routed to facilitate a certain UltraCSP designs.
BCB2 Opening (Via): Opening in the second layer of BCB which will define the metal exposure (wettable area) of the UBM pad. BCB2 will cover all re-distribution traces to protect metal runners from corrosion and physical damage.
Bond Pad: Exposed final metal portion of the device I/O (see also, Pad).
Bump: A small metal alloy deposit on the die that is melted to a pad on the board to form the electrical connection between the board and the die.
Bump Diameter: The widest measurement through the center cross-section of a re-flowed bump.
Bump Height: Vertical measurement from the top of the device passivation to the top of the bump after reflow (not yet attached to PCB substrate). After assembly, the analogous measurement is called "stand-off height".
Bump Shear: Shear value (force measured in grams) and failure mode measured during ball shear test.
Bump Standoff Height: Measurement from FR4 surface to silicon surface
Cu Pad: Solder receiving pad on the substrate that is Cu etch-defined.
Die (Chip): A square or rectangular piece cut from the wafer that contains the electrical pattern and is repeated in several rows and columns across the top surface of the wafer.
Die (Chip) Size: The active silicon chip area bounded on the outside by the scribe street.
Die (Chip) Stepping Distance: The distance between one point on a die and the same point on an adjacent die. This measurement takes into account both the die size along with the width of the street.
DNP: Distance to neutral point. The distance from an I/O to the center of the die. Maximum DNP defines the largest array size for a given process technology that will meet the minimum thermal fatigue performance criteria as established by FlipChip.
EliteCSP: A WLCSP product line that is specifically designed for bumping applications that require rapid cycle times, quick time to market, low bumping costs, and high temperature stability. Utilizes a plated Nickel UBM.
ESD: (Electrostatic discharge) The release of static electricity from one surface to another. Because IC devices and assemblies may be damaged by ESD, precautions are taken to eliminate ESD in IC manufacturing and test areas.
Final Metal: Uppermost metal layer in a device. This layer is usually covered with a thick dielectric passivation.
Flip Chip: A die that has bumps to create the electrical connection between the die and the board. So called because the die has to be flipped over in order to be assembled.
I/O: The location of the signal interfaces that contacts to the "outside" world.
I/O Final Metal Bond Pad: Same as I/O
I/O Metal Pad Size: Size of metal bond pad on an I/O, as manufactured during normal IC processing.
Maximum DNP: DNP stands for Distance to Neutral Point. A maximum DNP is the distance from the furthest I/O (solder bump) to the minimum stress point on the die. For a symmetric array pattern, it is also the geometric center of the die.
MDIF: (Mask Design Information Form) FlipChip information form that provides FlipChip with a description of the wafer, the die, and how you would like to bump it.
NSMD: (Non-Solder Mask Defined) PCB Copper pads that are smaller than the solder mask openings.
Pad: Metal area on the die that the bump or wire is attached to (see also, Bond Pad).
Partial Die: An incomplete die usually located on the edge of the wafer.
Passivation: Uppermost layer on an IC. Used for circuit protection and cushioning. Typically Nitride, Polyimide, Oxide, or Oxi-Nitride.
Peripheral: The edge of the die. Used to describe bumps that are placed near the edges of the die.
PO: (Passivation Opening) Opening in the passivation over the I/O final metal bond pads.
PCB: Printed Circuit Board.
Pitch: The linear distance between the centers of two adjacent I/Os or bumps.
PIQ: (Polyimide Isoindoro Quinazorindione) Dielectric polymer material used as a passivation layer in some semiconductor devices.
Repassivation: Layer of Passivation added by FlipChip as part of the bumping process. This layer adds robustness and can correct inappropriate Passivation Openings and Final Metal Pads. The repassivation layer is typically BCB or Spheron Polymer.
RDL: (Re-Distribution Line) Metal deposited at the same time as the UBM pad for the purpose of re-routing I/O sites, for example from edge-distributed bond pads used in wire-bonded applications, to an array layout. Also broadly used to describe the process of rerouting I/O.
SMD: (Solder Mask Defined) PCB pads that have solder-mask openings smaller than the copper pads.
Solder Mask: A layer of passivation material covered on top of outer-layer conductor (Cu) that has openings to allow solder wet to the Cu pads and prevents solder bridging in the rest area. These openings are called Solder Mask Openings.
Solder Paste: Reflowable pre-mixed solder paste that is printed and formed into a solder sphere. Provides the electrical connection between the die and the package substrate or printed circuit board. Since it is premixed, it provides for excellent composition control. Typically made up of two to four metals.
Solder/Flux Ratio: The volume ratio of flux to solder in the solder paste. A 50/50 ratio of solder to flux is recommended.
Spheron™: New FlipChip WL-CSP product predominately used in high frequency applications.
Stencil Aperture Opening: The laser-cut, Nickel Additive (E-Fab), Chemically Etched, or Electroform aperture openings on the solder paste stencil.
Stepping Distance: Linear measurements in both the x and y directions comprising die size and to the center of the scribe streets on all four sides. (see die stepping distance)
Street: The non-electrically active area on the wafer in between the die. Also known as the Saw Street.
UBM: (Under-Bump-Metallurgy) The metal stack that is deposited under the bump as part of the solder bumping process. It has the combined features of adhesion layer, diffusion barrier, wetting layer and oxidation protection layer. FlipChip uses NiV/Cu, Al/NiV/Cu, or Al/NiV/Cu/Ti/NiV/Cu as the UBM.
Wafer: A round flat disk most often made of silicon that is patterned with several die by semiconductor thin-films processing. Each wafer has a flat or notch cut into its edge to help with aligning or orienting the wafer.
Wafer Map: A representation of the wafer that notes where all of the defective die are located.
Wire Bond: The electrical connection consisting partially of a wire that bridges the die to the board.
WLP: Wafer level package.