Flip chip ( flip chip mounting) is a method of packaging integrated circuits , in which the chip is installed on the terminals made directly on its pads, which are located on the entire surface of the chip chip.
Content
Definitions
Bump ( bump ) - the contact pad, placed on the surface of the chip chip.
An input-output cell is an element of an integrated circuit transmitting input (output) signals to and from the circuit.
Wire bonding is a wrapping method in which the contact pads located on the periphery of the chip chip are connected to the case leads using wire conductors.
In terms of topological design
The inclusion of modern VLSI in electronic equipment is carried out through the input-output cells. Each input / output cell is connected to a contact pad (bump), which are connected to the external terminals of the microcircuit housing. I / O cells are divided into signal cells, which are used to transmit digital signals, and ground / power cells [1] . When using flip chip technology, the crystal power supply is connected directly to the bumps. Therefore, I / O ground / power cells provide ground and power exclusively for signal cells. In order to install the crystal using flip chip technology, it is necessary to place bumps over the entire area of the crystal. Bumps are divided into signal bumpers, ground bumps / power core chips and bumps ground / power I / O cells. Signal bumpers and ground / power bumpers of I / O cells are connected to the corresponding I / O cells along the shortest path in the uppermost metallization layers [2] . Earth / core power bumps are plugged into the chip's power supply. The total number of bumps is limited by the housing of the microcircuit and the traceability at the packaging stage. The number of signal bumps is equal to the number of signal I / O cells. The remaining ones are reserved for food. Flip chip technology allows you to place I / O cells not only along the perimeter of the chip, but also inside it.
Advantages of flip chip technology over wire bonding
- A more uniform distribution of power over the crystal;
- Better heat dissipation from the crystal;
- Greater flexibility in placing I / O cells on a chip;
- A shorter interconnect length, and, consequently, more compact dimensions, high performance devices [3] .
Implementation
Crystal bumps are soldered to the contact pads of the body using special solder balls, which are melted by the action of hot air.
Literature
- ↑ Golshan Khosrow. Physical Design Essentials An ASIC Design Implementation Perspective. — Springer, 2007.—P. 222.
- ↑ System Cadence Design. Innovus User Guide. Product Version 16.12.—2016.—P. 1749.
- ↑ George Rirely, Introduction to Flip Chip: What, Why, How Flipchips.com October 2000.