Thin-film capacitor and method of manufacturing the same

Abstract

A thin-film capacitor element having two conductive films and a dielectric film sandwiched therebetween is provided above a substrate. An inorganic protective film covering the thin-film capacitor element and having a second opening exposing at least a part of the conductive films is provided. An organic protective film covering the thin-film capacitor element from above the inorganic protective film and having a first opening therein, which is larger than the second opening and exposes the second opening, is provided. Besides, a bump connected with the conductive films via the first opening and the second opening is provided.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing a theoretical structure of the present invention;

FIGS. 2A to 2H are sectional views showing a manufacturing method of a thin-film capacitor according to a first embodiment of the present invention in the order of steps;

FIG. 3 is a sectional view showing a vicinity of a solder bump 27 of the thin-film capacitor according to the first embodiment in an enlarged manner;

FIG. 4 is a sectional view showing the vicinity of the solder bump 27 of the thin-film capacitor according to a second embodiment in an enlarged manner;

FIG. 5 is a sectional view showing the vicinity of the solder bump 27 of the thin-film capacitor according to a third embodiment in an enlarged manner;

FIG. 6 is a sectional view showing the vicinity of the solder bump 27 of the thin-film capacitor according to a fourth embodiment in an enlarged manner;

FIG. 7 is a sectional view showing the vicinity of the solder bump 27 of the thin-film capacitor according to a fifth embodiment in an enlarged manner;

FIG. 8 is a sectional view showing the vicinity of the solder bump 27 of the thin-film capacitor according to a sixth embodiment in an enlarged manner;

FIG. 9 is a sectional view showing the vicinity of the solder bump 27 of the thin-film capacitor according to a seventh embodiment in an enlarged manner;

FIG. 10 is a sectional view showing the vicinity of the solder bump 27 of the thin-film capacitor according to an eighth embodiment in an enlarged manner;

FIG. 11 is a sectional view showing a structure of a conventional thin-film capacitor; and

FIG. 12 is a view reproducing a photomicrograph taking the section in the vicinity of the electrode and the solder bump of an actual thin-film capacitor.

Claims

1. A thin-film capacitor comprising: a thin-film capacitor element having two conductive films and a dielectric film sandwiched therebetween;an inorganic protective film covering said thin-film capacitor element and having a second opening formed therein, the second opening exposing at least a part of said conductive film;an organic protective film covering said thin-film capacitor element from above said inorganic protective film and having a first opening formed therein, the first opening exposing said second opening and being larger than said second opening; anda bump connected with said conductive film via the first and second openings.

2. The thin-film capacitor according to claim 1, wherein a diameter of said second opening is equal to or smaller than one eighth of a diameter of said first opening.

3. The thin-film capacitor according to claim 1, wherein two or more pieces of said second opening are formed inside said first opening.

4. The thin-film capacitor according to claim 1, wherein a photosensitive resin film is formed as said organic protective film.

5. The thin-film capacitor according to claim 4, wherein one kind of film selected from a grope consisting of a polyimide resin film, an epoxy resin film, a Bsmaleimide-Triazine resin film, a polytetrafluorethylene resin film, a benzocyclobutene resin film, an acrylic resin film and a diallyl phthalate resin film is formed as said photosensitive resin film.

6. The thin-film capacitor according to claim 1, wherein a composite oxide film containing at least one kind of element selected from a group consisting of Sr, Ba, Pb, Zr, Bi, Ta, Ti, Mg and Nb is formed as said dielectric film.

7. The thin-film capacitor according to claim 1, wherein an amorphous metal oxide film is formed as said dielectric film.

8. The thin-film capacitor according to claim 1, wherein one kind of film selected from a group consisting of an Al2O3 film, an SiO2 film, an Si3N4 film and an SiON film is formed as said inorganic protective film.

9. The thin-film capacitor according to claim 1, wherein a film made of a same material as of said dielectric film is used as said inorganic protective film.

10. The thin-film capacitor according to claim 1, wherein at least one kind of film selected from a group of consisting of an Au film, a Cr film, a Cu film, a W film, a Pt film, a Pd film, a Ru film, a Ru oxide film, an Ir film, an Ir oxide film and a Pt oxide film is formed as the conductive film.

11. The thin-film capacitor according to claim 1, wherein said thin-film capacitor element is formed above one kind of substrate selected from a group consisting of a silicon substrate, a glass substrate and a saffhire substrate.

12. The thin-film capacitor according to claim 1, further comprising a conductive material formed in said first and second openings and having a Young's modulus of 15×1010 Pa or less, wherein said bump is formed on said conductive material.

13. The thin-film capacitor according to claim 12, wherein a conductive layer made of a conductive paste is formed as said conductive material.

14. The thin-film capacitor according to claim 13, wherein an Ag paste or a carbon paste is used as the conductive paste.

15. The thin-film capacitor according to claim 12, wherein a Cu film is formed as said conductive material.

16. A manufacturing method of a thin-film capacitor, comprising the steps of: forming a thin-film capacitor element having two conductive films and a dielectric film sandwiched therebetween above a substrate;forming an inorganic protective film covering said thin-film capacitor element;forming an organic protective film covering said thin-film capacitor element from above said inorganic protective film;forming a first opening in said organic protective film;forming a second opening at such a portion of said inorganic protective film that is exposed from said first opening, said second opening exposing at least a part of said conductive film and being smaller than said first opening; andforming a bump to be connected with the conductive film via said first and second openings.

17. The manufacturing method of a thin-film capacitor according to claim 16, wherein a diameter of said second opening is made equal to or smaller than one eighth of a diameter of said first opening.

18. The manufacturing method of a thin-film capacitor according to claim 16, wherein two or more pieces of said second opening are formed inside said first opening.

19. The manufacturing method of a thin-film capacitor according to claim 16, further comprising the step of forming a conductive material inside said first and second openings, between the step of forming second opening and the step of forming said bump, the conductive material having a Young's modulus of 15×1010 Pa or less.

20. The manufacturing method of the thin-film capacitor according to claim 19, wherein the step of forming said conductive material comprises the steps of: burying a conductive paste in said first and second openings; andcuring said conductive paste.