Process for making semiconductor electrode bumps by metal cluster ion deposition and etching
AssigneesMicroelectronics and Computer Technology Corporation, Hughes Aircraft Company
InventorsNalin Kumar, Chenggang Xie, Rama R. Goruganthu, Mohammed K. Ghazi
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Abstract
Ionized metal cluster beam deposition of metal bumps on substrates such as multi-chip modules and integrated circuit chips is enhanced. The present invention discloses wet etching techniques for removing unwanted metal deposited on the substrate around bumps, and multiple sources for depositing alloyed (tin-lead) bumps with constant composition.
Claims29
A method of depositing electrical connection bumps on spaced pad areas of an electrical substrate and removing deposits between the bumps, said method comprising the steps of:
- depositing a metal on the pad areas by ionized metal cluster beam deposition so that metallic bumps are formed on the pad areas;
- and
- etching enough metal from the substrate to prevent any metal deposited outside the bumps from connecting the bumps while only partially removing the bumps.
A method of depositing electrical connection bumps on spaced pad areas of an electrical substrate and removing deposits between the bumps, said method comprising the steps of:
- depositing a first metal on the pad areas by ionized metal cluster beam deposition so that first metallic bumps are formed on the pad areas;
- depositing a second metal on the first bumps so that second metallic bumps are formed on and at least partially cover the first bumps;
- etching enough second metal from the substrate to prevent any second metal outside the second bumps from connecting the second bumps while only partially removing the second bumps such that the second bumps continue to at least partially cover the first bumps, and such that any first metal deposited outside the first bumps which forms a continuous path between the first bumps is at least partially exposed;
- and
- etching enough first metal from the substrate to prevent any first metal deposited outside the first bumps from connecting the first bumps while at most only partially removing the first bumps.
A method of depositing alloyed electrical connection bumps on spaced pad areas of an electrical substrate, said method comprising the steps of:
- depositing a first metal over the pad areas by ionized metal cluster deposition from a first source;
- depositing a second metal over the pad areas by ionized metal cluster deposition from a second source separate from the first source;
- and then
- alloying the deposited first and second metals, thereby forming alloyed metallic bumps on the pad areas.
Dependencies are inferred from the claim text.