Semiconductor device with side wall protection film for bond pad and wiring

Abstract

The method of manufacturing a semiconductor device includes: forming a conductive film including a first metal-containing film and an anti-reflection film including a second metal-containing film which is laminated on the first metal-containing film, the second metal-containing film being different from the first metal-containing film and laminated on the first metal-containing film; patterning the conductive film; forming side wall protection films on side surfaces of the patterned conductive film; etching the anti-reflection film in the patterned conductive film, after formation of the side wall protection films; forming a passivation film on the first metal-containing film and the side wall protection films; and forming, in the passivation film, an opening portion in which a part of a top surface of the first metal-containing film is exposed.

Claims

1. A semiconductor device, comprising: a bonding pad and a wiring each in the same wiring layer composed of a metal-containing film, and adjacent to each other across a distance of 1 m or less; side wall protection films on side surfaces of the bonding pad and side surfaces of the wiring, the side wall protection films comprising one of silicon oxide films and silicon nitride films; and a passivation film covering a top surface of the bonding pad, a top surface of the wiring, and surfaces of the side wall protection films, and having an opening portion exposing a part of the top surface of the bonding pad, the passivation film in direct contact with the top surface of the bonding pad and the top surface of the wiring.

2. The semiconductor device according to claim 1, further comprising a barrier metal layer located below the metal-containing film, the barrier metal layer including one of a titanium film, a titanium nitride film, and a laminated film including a titanium film and a titanium nitride film.

3. The semiconductor device according to claim 1, wherein the metal-containing film is one of an aluminum film and an aluminum alloy film.

4. The semiconductor device according to claim 3, further comprising a barrier metal layer located below the metal-containing film, the barrier metal layer including one of a titanium film, a titanium nitride film, and a laminated film including a titanium film and a titanium nitride film.

5. The semiconductor device according to claim 1, further comprising a barrier metal layer located below the metal-containing film, the barrier metal layer including one of a titanium film, a titanium nitride film, and a laminated film including a titanium film and a titanium nitride film.

6. The semiconductor device according to claim 1, wherein the passivation film is one of a silicon oxide film, a silicon nitride film, and a laminated film including a silicon oxide film and a silicon nitride film.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

(2) FIG. 1 is a sectional view for illustrating one of steps of manufacturing a semiconductor device according to an embodiment of the present invention;

(3) FIG. 2 is a sectional view for illustrating one of steps of manufacturing the semiconductor device following the step of FIG. 1 according to the embodiment of the present invention;

(4) FIG. 3 is a sectional view for illustrating one of steps of manufacturing the semiconductor device following the step of FIG. 2 according to the embodiment of the present invention;

(5) FIG. 4 is a sectional view for illustrating one of steps of manufacturing the semiconductor device following the step of FIG. 3 according to the embodiment of the present invention;

(6) FIG. 5 is a sectional view for illustrating one of steps of manufacturing the semiconductor device following the step of FIG. 4 according to the embodiment of the present invention;

(7) FIG. 6 is a sectional view for illustrating one of steps of manufacturing the semiconductor device following the step of FIG. 5 according to the embodiment of the present invention; and

(8) FIG. 7A and FIG. 7B are sectional views for illustrating steps of manufacturing a semiconductor device of the related art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(9) The invention will now be described herein with reference to illustrative embodiments.

(10) FIG. 1 to FIG. 6 are sectional views for illustrating steps of manufacturing a semiconductor device according to an embodiment of the present invention.

(11) As illustrated in FIG. 1, a conductive film (also referred to as wiring layer) 10 is formed on an interlayer insulating film 1 which is formed on a semiconductor substrate (not shown). The conductive film 10 has a laminated structure in which different kinds of metals are laminated by sequentially depositing, by means of sputtering or the like, materials of a barrier metal layer 11, a metal film (also referred to as first metal-containing film) 12, and an anti-reflection film (also referred to as second metal-containing film) 13. The barrier metal layer 11 is formed by layering a titanium nitride film and a titanium film in this order. The metal film 12 is made from aluminum. The anti-reflection film 13 is made from titanium nitride. A photoresist pattern (not shown) is then formed on the conductive film 10 in a photolithography step, and the conductive film 10 is patterned with the photoresist pattern as a mask, to thereby form a bonding pad 21 and a wiring 22.

(12) Next, as illustrated in FIG. 2, an insulating film 31 including a silicon oxide film, is formed by CVD on the entire surface so as to cover top and side surfaces of the patterned conductive film 10, that is, the bonding pad 21 and the wiring 22.

(13) As illustrated in FIG. 3, the insulating film 31 is subsequently etched back by anisotropic dry etching. The etching back lasts until a top surface of the anti-reflection film 13 is exposed. Side wall protection films 32 are thereby formed on side surfaces of the bonding pad 21 and the wiring 22.

(14) After the formation of the side wall protection film 32, as illustrated in FIG. 4, the anti-reflection film 13 is removed by dry etching, or by etching using a hydrogen peroxide solution or other chemical solution. In the etching, the anti-reflection film 13 can be removed entirely without etching the barrier metal layer 11 which is composed of a film containing titanium which is the same as the titanium nitride film constituting the anti-reflection film 13, because the side walls of the bonding pad 21 and the wiring 22 are protected by the side wall protection films 32 composed of silicon oxide films. The conductive film 10 is accordingly prevented from developing a notch.

(15) Next, as illustrated in FIG. 5, a passivation film 41 which is a laminated film including a silicon oxide film and a silicon nitride film, is formed by CVD so as to cover the entire surface including a top surface of the metal film 12 and surfaces of the side wall protection films 32. A situation in which the passivation film 41 fails to be formed in places can be avoided in this step because no notch is generated under the bonding pad 21. Another advantageous effect is that the side wall protection films 32 lessen steepness of the shape of level differences of the bonding pad 21 and the wiring 22, to thereby allow deposition of the passivation film 41 with an excellent coverage. Cracking and other problems in the passivation film can therefore be prevented, which improves reliability.

(16) Next, as illustrated in FIG. 6, a photoresist pattern (not shown) having an opening above the bonding pad 21 is formed and used as a mask in a subsequent photolithography step to pattern the passivation film 41 and to form an opening portion 42 above a part of the bonding pad 21. The part of the top surface of the bonding pad 21 that is exposed in the opening portion 42 is thus made into a bonding pad portion. In the step of FIG. 6, the anti-reflection film 13 which has already been removed in the steps illustrated in FIG. 2 to FIG. 3, is not exposed on an inner side surface of the opening portion 42, and the battery effect can therefore be prevented.

(17) Generally, an anti-reflection film is used in the patterning of a metal film in order to accomplish desired patterning with high precision, namely, a minute wiring width and wiring space. The width of the wiring 22, the space between the bonding pad 21 and the wiring 22, and the space between wiring wires (not shown) (they are both referred to as wiring space) are accordingly very narrow in this embodiment. For example, the wiring width is 1 m or less, and the wiring space is 1 m or less.

(18) According to this embodiment, even with that minute wiring width and wiring space, the metal film 12 can be patterned with high precision with the use of the anti-reflection film 13, the battery effect can be prevented, no notch is generated at a lower edge of the bonding pad 21, and the passivation film 41 can be formed with an excellent coverage. A highly reliable semiconductor device can thus be obtained according to this embodiment.

(19) It is apparent that the present invention is not limited to the above embodiments, and may be modified and changed without departing from the scope and spirit of the invention.

(20) For instance, while the embodiment described above deals with an example of removing the anti-reflection film 13 by dry etching or by etching using a hydrogen peroxide solution or other chemical solution, the present invention is not limited thereto. The anti-reflection film 13 may be removed by performing continuously etching in the etching back step of the insulating film 31, until the metal film 12 is exposed.

(21) The side wall protection films may be a silicon nitride film instead of the silicon oxide film.

(22) The embodiment described above deals with an example in which the first metal-containing film is an aluminum film and the second metal-containing film (anti-reflection film) is a titanium nitride film. However, the first metal-containing film may be an aluminum alloy film, and the second metal-containing film may be a titanium film.

(23) The passivation film which is a laminated film including a silicon oxide film and a silicon nitride film in the example of the embodiment described above, may be a single-layer silicon oxide film or a single-layer silicon nitride film.