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PCM based antifuse

IP.com Disclosure Number: IPCOM000229258D
Publication Date: 2013-Jul-17
Document File: 5 page(s) / 201K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is an anti-fuse interconnect structure with embedded phase change materials (PCM) between metal lines. The PCM can switch between amorphous and crystalline to disable or enable the antifuse conductive path. As a result, the programming power can be very low. This approach requires no extra layer of anti-fuse material, and uses adjustable and low programming power (below 2V or 5mA).

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PCM based antifuse

Traditional anti-fuse structure requires additional anti-fuse dielectrics, many extra masks, high breakdown voltage, large layout area, and limitations on design flexibility.

Figure 1: Traditional anti-fuse structure

The invention is an anti-fuse interconnect structure with embedded phase change materials (PCM) between metal lines. The PCM can switch between amorphous and crystalline to disable or enable the antifuse conductive path. As a result, the programming power can be very low. This approach requires no extra layer of anti-fuse material, and uses adjustable and low programming power (below 2V or 5mA).

The PCM works in the following way:


• Amorphous crystalline: slow anneal to a temperature above 1200C


• Crystalline amorphous: raise to melt temperature (below 7000C) followed by a fast quench

Figure 2: How the PCM works

The first proposed structure is comprised of the following components and functions:


1. Control current flows from V1+ to V1- (More resistive TaN, lower current)


2. Antifuse consists of M1+ and M1- bridged with phase change material


3. PCM element can be GexSby, GexSbyTez, SbxTey, etc.

4. Phase change material changes from high resistance amorphous to low resistance crystalline by TaN heater

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Figure 3: Proposed Structure I

The second proposed structure is comprised of the following components and functions:


1. Control current flows from M1+ to M1- (More resistive TaN, lower current)


2. Antifuse consists of V1+ and V1- bridged with phase change material

Figure 4: Proposed Structure II

Figure 5: Integration Method, Step 1

Figure 6: Integration Method, Step 2

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Figure 7: Integration Method, Step 3

Figure 8: Integration Method, Step 4

Example Embodiment: Finite Element Model

1. Distance from metal end to ILD boundary in all X, Y and Z directions is 10 times the metal width to accurately capture temperature rise


2. An electrical current is forced to the via shown

on left side on the model, while via on right

side is electrically grounded

3. Dielectric cap...