An Independent Journal Dedicated to the Advancement of Chip - Scale Electronics July - August 2000 Email the editor

Figure 1. In FleXBGAs and TapeArray BGAs, die are wire bonded to tape substrates. The former are manufactured and tested as single units; the latter in arrays.	Figure 2 . ChipArray packages are near-CSP in scale.

The FleXBGA (Figure 1) is manufactured in single-unit format, singulated and tested, while the Tape Array BGA is manufactured and tested in an array format. Otherwise the two are similar.

Both are die-down, wire-bonded, tape substrate packages in 5 to 27-mm body sizes with 48 to 672 balls.

The ChipArray (Figure 2) enables the package to be no more than 1.5 mm larger than the chip itself.

Figure 3. Amkor's SuperBGA packages incorporate heat sinks for power dissipation.

Amkor's SuperBGA (Figure 3) provides a copper heat-sink for heat dissipation and is designed for very low-profile, high-power applications.

Figure 4. The µBGA is a true-chip-scale package.	Figure 5. Amkor's MicroLeadFrame (MLF) package is ideal for ICs with 48 leads or fewer, where leadframe-based packages are more economical to manufacture than area-array packages.

The µBGA package (Figure 4), which uses a tape substrate, rather than a plastic laminate, is approximately the same size as the chip.

The Amkor's MicroLeadFrame package technology (Figure 5) improves upon previous TQFP and TSOP technologies by eliminating leads, shortening the wire lengths to the die, and providing capability for thermal dissipation or electrical performance improvement. These packages can accommodate a die size almost equal to the package size.

The MLF design allows the leadframe's metal die-attach paddle to be exposed on the bottom of the package. This enables designers to achieve a stable low-impedance ground by using down-bonds or a conductive die-attach material. When soldered directly to the system board, the paddle also provides an efficient heat path.

High pin-count (HP) BGAs are future flip-chip packages that accommodate more than 700 balls on a 1.0-mm pitch in packages measuring 31 to 45 mm on a side. The table below shows HP BGAs presently available. From 680 to 1936 balls are possible at a 1.0-mm pitch.