Browse Prior Art Database

New Laser-Anti-Fuse Devices for BCD Applications

IP.com Disclosure Number: IPCOM000125774D
Original Publication Date: 2005-Jul-25
Included in the Prior Art Database: 2005-Jul-25
Document File: 1 page(s) / 497K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

Chips are provided with read-only, permanent information at waver stage. In order to store the information into the chip for now two methods are used: "Zap-Diodes" and "Laser-Fuse Structures". Both have disadvantages: Using the Zap-Diodes the chips must be extended in space by additional pads, such as the chip is enlarged significantly. Using the Laser-Fuse-Structures an opening into the passivation layer is required, which results in a risk of corrosion of the inner components.

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New Laser-Anti-Fuse Devices for BCD Applications

Idea: Nicola Vannucci, AT-Villach

Chips are provided with read-only, permanent information at waver stage. In order to store the information into the chip for now two methods are used: "Zap-Diodes" and "Laser-Fuse Structures". Both have disadvantages: Using the Zap-Diodes the chips must be extended in space by additional pads, such as the chip is enlarged significantly. Using the Laser-Fuse-Structures an opening into the passivation layer is required, which results in a risk of corrosion of the inner components.

It is proposed to use devices called "Anti-Fuses" to store read-only, permanent information into the chip at waver stage. Anti-Fuses are structures that first act like an opened circuit and after irradiation by an appropriate laser pulse they act like a shortened circuit (Fig. 1). The chip is therefore easily programmed by applying laser pulses. The two realizations "Via" and "Volcano" Anti-Fuses (Fig. 2) can be used in this manner to store the information. There is no need to open the chip to the passivation layer. The Anti-Fuse is "burned" by applying an appropriate laser beam. The electrical contact inside the Anti-Fuse is achieved by an enlargement of a metal pad due to the laser beam and a following melting/flowing process of the metal to another metal pad.

Fig. 1: Cross-Section of the proposed Anti-Fuse

Fig. 2: Cross-Section of the proposed "Via"-Anti-Fuse

© SIEMENS AG 2005 file: ifx_2005J51889.doc...