SEMICONDUCTOR DEVICE AND A METHOD OF INCREASING A RESISTANCE VALUE OF AN ELECTRIC FUSE

Abstract

Provided is a semiconductor device having an electric fuse structure which receives the supply of an electric current to be permitted to be cut without damaging portions around the fuse. An electric fuse is electrically connected between an electronic circuit and a redundant circuit as a spare of the electronic circuit. After these circuits are sealed with a resin, the fuse can be cut by receiving the supply of an electric current from the outside. The electric fuse is formed in a fine layer, and is made of a main wiring and a barrier film. The linear expansion coefficient of each of the main wiring and the barrier film is larger than that of each of the insulator layers. The melting point of each of the main wiring and the barrier film is lower than that of each of the insulator layers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating a structure of an electronic circuit to which an electric fuse of an embodiment of the invention is fitted.

FIG. 2 is a view illustrating a structure of the whole of a semiconductor device wherein an electric fuse structure of the embodiment is formed.

FIG. 3 is a schematic view illustrating the electric fuse of the embodiment which has a meandering shape.

FIG. 4 is a sectional view taken on line IV-IV in FIG. 3.

FIG. 5 is a schematic view illustrating the electric fuse of the embodiment which is made only of a liner portion.

FIG. 6 is a sectional view taken on line VI-VI in FIG. 5.

FIG. 7 is a schematic view illustrating another example of the electric fuse of the embodiment which has a meandering shape.

FIG. 8 is a photograph showing a state that linear portions of an electric fuse of the embodiment which has a meandering shape contact each other by leakage or solid dissolution.

FIG. 9 is a view illustrating a basic example of the electric fuse structure of the embodiment.

FIG. 10 is a first different example of the electric fuse structure of the embodiment.

FIG. 11A is a second different example of the electric fuse structure of the embodiment.

FIG. 11B is a third different example of the electric fuse structure of the embodiment.

FIG. 12A is a fourth different example of the electric fuse structure of the embodiment.

FIG. 12B is a fifth different example of the electric fuse structure of the embodiment.

FIG. 13 is a sixth different example of the electric fuse structure of the embodiment.

FIG. 14A is a seventh different example of the electric fuse structure of the embodiment.

FIG. 14B is an eighth different example of the electric fuse structure of the embodiment.

FIG. 15 is a ninth different example of the electric fuse structure of the embodiment.

FIG. 16A is a tenth different example of the electric fuse structure of the embodiment.

FIG. 16B is an eleventh different example of the electric fuse structure of the embodiment.

FIG. 17 is a twelfth different example of the electric fuse structure of the embodiment.

FIG. 18A is a thirteenth different example of the electric fuse structure of the embodiment.

FIG. 18B is a fourteenth different example of the electric fuse structure of the embodiment.

FIG. 19 is a fifteenth different example of the electric fuse structure of the embodiment.

FIG. 20A is a sixteenth different example of the electric fuse structure of the embodiment.

FIG. 20B is a seventeenth different example of the electric fuse structure of the embodiment.

FIG. 21 is a view for explaining the direction of force acting on the electric fuse which is the basic example of the embodiment when an electric current flows into this electric fuse.

FIG. 22 is a view for explaining a state that the electric fuse of the basic example swells.

FIG. 23 is a top view illustrating a first state of the electric fuse of the basic example when it is cut.

FIG. 24 is a sectional view taken on line XXIV-XXIV in FIG. 23.

FIG. 25 is a top view illustrating a second state of the electric fuse of the basic example when it is cut.

FIG. 26 is a sectional view taken on line XXVI-XXVI in FIG. 25.

FIG. 27 is a top view illustrating a third state of the electric fuse of the basic example when it is cut.

FIG. 28 is a sectional view taken on line XXVIII-XXVIII in FIG. 27.

FIG. 29 is a top view illustrating a fourth state of the electric fuse of the basic example when it is cut.

FIG. 30 is a sectional view taken on line XXX-XXX in FIG. 29.

FIG. 31 is a top view illustrating a fifth state of the electric fuse of the basic example when it is cut.

FIG. 32 is a sectional view taken on line XXXII-XXXII in FIG. 31.

FIG. 33 is a photograph (of a cross section) showing a state that an electric fuse is absorbed into a crack formed in an insulator layer in an electric fuse structure.

FIG. 34 is a photograph (of a top face) showing the state that the electric fuse is absorbed into the crack formed in the insulator layer in the electric fuse structure.

FIG. 35 is a view illustrating an electric current pulse as an improper pulse, and an electric current pulse as a proper pulse.

FIG. 36 is a photograph showing an electric fuse cut by an electric current pulse as an improper pulse, and an electric fuse cut by an electric current pulse as a proper pulse.

FIG. 37 is a graph showing a relationship between rise time of electric current pulses and the ratio of the resistance of an electric fuse after the fuse is cut to that of the electric fuse before the fuse is cut.

FIG. 38 is a top view illustrating an example of the position of a cut portion of an electric fuse made only of a linear portion.

FIG. 39 is a chart wherein positions of cut portions of plural electric fuses each made only of a linear portion are plotted.

FIG. 40 is a view for explaining an electric fuse structure wherein a central portion is selectively to be cut.

FIG. 41 is a photograph showing an electric fuse structure wherein a central portion was selectively cut.

FIG. 42 is a view illustrating the distance between linear portions.

FIG. 43 is a view illustrating a state that linear portions short-circuit through a cut piece.

FIG. 44 is a view illustrating an electric fuse structure having a construction for preventing linear portions from short-circuiting.

FIG. 45 is a view for explaining a method of cutting an electric fuse by use of pinch effect.

FIG. 46 is a photograph showing an electric fuse cut by pinch effect.

FIG. 47 is a graph of a relationship between time and the distance between a moiety having a temperature of 600° C. when the temperature of an electric fuse was kept at 1200° C. and the electric fuse.

Claims

1. A semiconductor device, comprising: an insulator layer; andan electric fuse which is formed in the insulator layer, and has a larger linear expansion coefficient than that of the insulator layer, and further has a lower melting point than that of the insulator layer.

2. The semiconductor device according to claim 1, wherein the electric fuse comprises: a main wiring; anda barrier film which contacts with each of the main wiring and the insulator layer,wherein the linear expansion coefficient of the barrier film is smaller than that of the main wiring and is larger than that of the insulator layer, andwherein the melting point of the barrier film is higher than that of the main wiring and is lower than that of the insulator layer.

3. The semiconductor device according to claim 2, wherein the main wiring comprises copper, aluminum or iron.

4. The semiconductor device according to claim 2, wherein the barrier film comprises a tantalum film.

5. The semiconductor device according to claim 2, wherein the barrier film comprises: a first tantalum film which contacts with the insulator layer;a tantalum nitride film which contacts with the first tantalum film; anda second tantalum film which contacts with the tantalum nitride film and the main wiring.

6. The semiconductor device according to claim 1, wherein the insulator layer comprises a first insulator layer having a trench in which the electric fuse is formed, and a second insulator layer formed over the first insulator layer and the electric fuse.

7. The semiconductor device according to claim 6, wherein the second insulator layer comprises a SiCN film, a SiN film, a bi-layered structure film having a SiCN film and a SiN film, or a low-k film having a dielectric constant of 3 or less.

8. The semiconductor device according to claim 1, wherein a cap film having a higher electric resistance than that of the main wiring is formed between the main wiring and the insulator layer.

9. The semiconductor device according to claim 1, wherein the electric fuse is surrounded by an electroconductive material floating electrically.

10. A semiconductor device, comprising: a semiconductor substrate;a gate electrode formed over the semiconductor substrate;an interlayer dielectric covering the gate electrode;a fine layer formed over the interlayer dielectric;a semiglobal layer formed over the fine layer;a global layer formed over the semiglobal layer; andan electric fuse formed in at least one selected from the fine layer, the semiglobal layer, and the global layer.

11. A semiconductor device, comprising: an insulator layer; andan electric fuse which is formed in the insulator layer, and has a meandering shape comprising a linear portion and a bent portion,the distance between moieties near the bent portion being smaller than the distance between moieties other than the moieties near the bent portion.

12. A method of increasing the resistance of an electric fuse according to a semiconductor device which comprises an insulator layer; and an electric fuse which is formed in the insulator layer, and has a larger linear expansion coefficient than that of the insulator layer, and further has a lower melting point than that of the insulator layer, the method of increasing the resistance of the electric fuse comprising the steps of: supplying an electric current to the electric fuse, thereby melting the electric fuse and further generating a crack in the insulator layer; andafter the step above, using a capillary phenomenon to cause a part of the melted electric fuse to be absorbed into the crack, thereby forming a discontinuous portion in the electric fuse.

13. The method according to claim 12, wherein the electric current is supplied as pulse waves to the electric fuse, and the rise time of the pulse waves is adjusted, thereby generating the crack.

14. A method of increasing the resistance of an electric fuse according to a semiconductor device which comprises an insulator layer; and an electric fuse which is formed in the insulator layer, and has a larger linear expansion coefficient than that of the insulator layer, and further has a lower melting point than that of the insulator layer, the method of increasing the resistance of the electric fuse comprising the steps of: supplying an electric current to the electric fuse, thereby making the electric fuse narrow by use of pinch effect; andstopping the supply of the electric current, thereby forming a cavity in the electric fuse by use of retaining force of the electric fuse.

15. The method according to claim 14, wherein the step of supplying the electric current and the step of stopping the supply of the electric current are alternately repeated.