| 摘要 |
A flip-chip bonding arrangement for use with for example, a GaAs monolithic microwave integrated circuit (MMIC) 42, or an opto-electronic device, has one or more metal under-bump portions 44 attached to a first substrate 40. Corresponding bump portions 52 of an interconnecting metal are attached to the surface of the under bump portions 44 remote from the first substrate. The arrangement is characterised in that the sides of the under-bump portions are non-wettable by the interconnecting metal, and the height of the under-bump portion substantially determines the overall separation between the first and a second substrates when the two are bonded. The under bump portions 44 may be made from nickel or copper, and have a height of at least 10 žm, and of at most 100 žm. A method of providing a flip-chip bonding arrangement uses a seed layer, photoresist, under bumps and bumps formed in openings in the photoresist (Figures 5a-5g). A further method of bonding two substrates uses a plurality of solder bumps and contact means. A thin layer of gold is deposited on the solder bumps. Without the application of a flux, the temperature of the solder-bumps is raised so that a solder connection is made between the bumps and the contact means. |
