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Method for Eliminating Laser Splatter Concerns Resulting From the Deletion of Fuses in Semiconductor Logic

IP.com Disclosure Number: IPCOM000037102D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Cronin, JE: AUTHOR [+2]

Abstract

A sacrificial coating is applied prior to logic testing and laser blowing of metal fuses, eliminating the need for "clean-up" of the splatter that results from blowing fuses.

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Method for Eliminating Laser Splatter Concerns Resulting From the Deletion of Fuses in Semiconductor Logic

A sacrificial coating is applied prior to logic testing and laser blowing of metal fuses, eliminating the need for "clean-up" of the splatter that results from blowing fuses.

Semiconductor logic generally uses multi-level wiring schemes, and it becomes impossible to blow polysilicon fuses after testing with a laser due to the thick multi-level insulation over the polysilicon level. Therefore, metal fuses are used; however, this technique requires a "clean-up" process following fuse blowing.

For passivated fuses, a thick insulation over the metal fuse areas is "opened- up" at the same time metal pads are defined in the final insulator passivation of the chip. When cleaning up residual metal to eliminate splatter-created shorts after blowing fuses, the final level metal pads are attacked. This concern may require a two mask process, i.e., a separate mask to protect the final level pad metal during "clean-up". Blowing final level unpassivated fuses is not currently an option because metal splatter may cause unwanted shorts and the splatter can not be removed without affecting all other metal pads, lines and unblown fuses. A technique is described for fixing this problem.

Through the application of a spin-applied photoresist or glass after final insulator passivation, via definition etch and before a wafer is sent to test, a sacrificial coat approximately 2,000...