Integrated circuit device having pads structure formed thereon and method for forming the same

Abstract

The invention is to provide a structure of IC pad and its forming method. The structure is arranged in an insulation layer and is comprised of a lower electric-conduction layer, a compound layer structure and a pad layer. The lower electric-conduction layer is arranged at an appropriate position in the insulation layer and is connected to an electric potential. The compound layer structure is arranged on the insulation layer and is composed of at least one electric-conduction layer and at least one electric-conduction connecting layer, both are inter-overlapped to each other. The pad layer is arranged on the compound layer structure.

Claims

1. An integrated circuit (IC) device having a pad structure formed thereon, the IC device comprising: a) a substrate; b) an insulation layer formed on the substrate; c) a .Iadd.plurality of electric-conduction layers formed in the insulation layer, including a .Iaddend.lower electric-conduction layer .[.formed in the insulation layer.]..Iadd., each electric-conduction layer having a thickness.Iaddend.; .Iadd.d) a plurality of connecting layers, each connecting layer having a thickness, the connecting layers interposed between the electric-conduction layers, the plurality of connecting layers selectively coupling one or more of the electric-conduction layers;.Iaddend. .[.d.]. .Iadd.e.Iaddend.) a compound layer structure formed in the insulation layer; .[.e.]. .Iadd.f.Iaddend.) a first pad layer formed on the insulation layer and coupled to the compound layer structure, wherein the first pad layer and the compound layer structure are spaced apart .[.from the lower electric-conduction.]. .Iadd.and substantially above from the lower electric-conduction layer, wherein the compound layer structure and the lower electric-conduction layer are spaced apart by the thickness of at least one electric-conduction layer and the thickness of at least one connecting .Iaddend.layer.Iadd., wherein the first pad layer is designated for signal transmission.Iaddend.; .[.and.]. .[.f.]. .Iadd.g.Iaddend.) a second pad layer formed on the insulation layer and coupled to the lower electric-conduction layer.Iadd., wherein the second pad layer is designated to be coupled to a power source; h) at least one second connecting layer for coupling the second pad layer to the lower electric-conduction layer; and i) at least one second electric-conduction layer coupled between the second pad layer and the lower electric-conduction layer with the second connecting layer.Iaddend..

2. The IC device according to claim 1, wherein the compound layer structure comprises a first electric-conduction layer and a first connecting layer to couple the first electric-conduction layer to the first pad layer.

3. The IC device according to claim 2, wherein the first connecting layer comprises a plurality of via plugs.

4. The IC device according to claim 2, wherein the first electric-conduction layer is shaped like a webbed railing.

5. The IC device according to claim 2, wherein the area of the first electric-conduction layer is smaller than that of the first pad layer.

6. The IC device according to claim 1, wherein the first pad layer is shaped like a polygon.

7. The IC device according to claim 1, further comprising a passivation layer formed on the insulation layer to cover a part of the outer rim of at least one of the first and second pad layers.

.[.8. The IC device according to claim 1, further comprising at least one second connecting layer for coupling the second pad layer to the lower electric-conduction layer..].

.[.9. The IC device according to claim 8, further comprising at least one second electric-conduction layer coupled between the second pad layer and the lower electric-conduction layer with the second connecting layer..].

10. .[.The IC device according to claim 1,.]. .Iadd.An integrated circuit (IC) device having a pad structure formed thereon, the IC device comprising: a) a substrate; b) an insulation layer formed on the substrate; c) a lower electric-conduction layer formed in the insulation layer; d) a compound layer structure formed in the insulation layer; e) a first pad layer formed on the insulation layer, substantially formed above the lower electric-conduction layer and coupled to the compound layer structure, wherein the first pad layer and the compound layer structure are spaced apart from the lower electric-conduction layer, wherein the first pad layer is designated for signal transmission; f) a second pad layer formed on the insulation layer and coupled to the lower electric-conduction layer, wherein the second pad layer is designated to be coupled to a power source; g) at least one second connecting layer for coupling the second pad layer to the lower electric-conduction layer; and h) at least one second electric-conduction layer coupled between the second pad layer and the lower electric-conduction layer with the second connecting layer and disposed lower than the compound layer structure;.Iaddend. wherein a noise from the substrate is kept away from the first pad layer by the lower electric-conduction layer.

11. An integrated circuit (IC) device having a pad structure formed thereon, the IC device comprising: a) a substrate; b) an insulation layer formed on the substrate; c) a lower electric-conduction layer formed in the insulation layer; d) a compound layer structure formed in the insulation layer; .[.and.]. e) a first pad layer formed on the insulation layer and coupled to the compound layer structure, wherein the first pad layer and the compound layer structure are spaced apart from the lower electric-conduction layer.Iadd., wherein the first pad layer is designated for signal transmission; f) a second pad layer formed on the insulation layer and coupled to the lower electric-conduction layer, wherein the second pad layer is designated to be coupled to a power source; g) at least one second connecting layer for coupling the second pad layer to the lower electric-conduction layer; and h) at least one second electric-conduction layer coupled between the second pad layer and the lower electric-conduction layer with the second connecting layer and disposed lower than the compound layer structure.Iaddend..

12. The IC device according to claim 11, wherein the compound layer structure comprises a first electric-conduction layer and a first connecting layer to couple the first electric-conduction layer to the first pad layer.

.[.13. The IC device according to claim 11, further comprising a second pad layer formed on the insulation layer and coupled to the lower electric-conduction layer..].

.[.14. The IC device according to claim 13, further comprising at least one second connecting layer for coupling the second pad layer to the lower electric-conduction layer; and at least one second electric-conduction layer coupled between the second pad layer and the lower electric-conduction layer with the second connecting layer..].

15. The IC device according to claim .[.14.]. .Iadd.11.Iaddend., wherein, the area of the first electric-conduction layer is smaller than that of the first pad layer.

16. The IC device according to claim 11, wherein the first pad layer is shaped like a polygon.

17. The IC device according to claim 11, further comprising a passivation layer formed on the insulation layer to cover a part of the outer rim of at least one of the first and second pad layers.

18. The IC device according to claim 11, wherein a noise from the substrate is kept away from the first pad layer by the lower electric-conduction layer.

19. A method for fabricating an IC device having a pad structure formed thereon, the method comprising: a) providing a substrate; b) forming an insulation layer formed on the substrate; c) forming a lower electric-conduction layer formed in the insulation layer, at least a part of the lower electric-conduction layer being covered by the insulation layer; d) forming a compound layer structure formed in the insulation layer, the compound layer structure being spaced apart from and not connected to the lower electric-conduction layer; .[.and.]. e) forming a first pad layer formed on the insulation layer, .[.the first pad layer being.]. coupled to the compound layer, wherein .[.in the forming a first pad layer step e).]. the first pad layer and the compound layer are spaced apart from the lower electric-conduction layer.Iadd.; f) forming a second pad layer formed on the insulation layer and coupled to the lower electric-conduction layer, wherein the second pad layer is designated to be coupled to a power source; g) forming at least one second connecting layer for coupling the second pad layer to the lower electric-conduction layer; and h) forming at least one second electric-conduction layer coupled between the second pad layer and the lower electric-conduction layer with the second connecting layer.Iaddend..

20. The method according to claim 19, wherein a noise from the substrate is kept away .[.form.]. .Iadd.from .Iaddend.the first pad layer by the lower electric-conduction layer.

21. The method according to claim 19, wherein the forming a compound layer structure step d) further comprises the steps of: forming at least one first electric-conduction layer on the insulation layer; and forming at least one first connecting layer on the insulation layer, wherein the first connecting layer is to couple the first electric-conduction layer to the first pad layer.

22. The method according to claim 21, wherein the area of the first electric-conduction layer is smaller than that of the first pad layer.

.Iadd.23. The IC device according to claim 1, wherein the lower electric-conduction layer is lowest in depth of the plurality of electric-conduction layers..Iaddend.

.Iadd.24. The IC device according to claim 1, wherein the at least one electric-conduction layer is not substantially disposed between the first pad layer and an area of the lower electric-conduction layer beneath the first pad layer..Iaddend.

.Iadd.25. The IC device according to claim 1, wherein the lower electric-conduction layer is disposed such that an area of the first pad layer substantially intersects the lower electric-conduction layer when superimposed on the lower electric-conduction layer..Iaddend.

.Iadd.26. The IC device according to claim 25, wherein the lower electric-conduction layer is comprised of a plurality of sub-layers disposed at the same depth..Iaddend.

.Iadd.27. The IC device according to claim 1, wherein the second pad layer is designated to be coupled to a ground potential..Iaddend.

.Iadd.28. The IC device according to claim 1, wherein the second pad layer is designated to be coupled to a voltage potential..Iaddend.

.Iadd.29. The IC device according to claim 1, wherein the first pad layer is designated to be coupled to a high frequency signal..Iaddend.

.Iadd.30. The IC device according to claim 10, wherein the compound layer structure comprises a first electric-conduction layer and a first electric-conduction connecting layer for coupling the first electric-conduction layer to the first pad layer..Iaddend.

.Iadd.31. The IC device according to claim 30, further comprising: a second electric-conduction layer, comprised of a first and second sub-layers at the same depth, a second electric-conduction connecting layer, comprised of first and second sub-layers at the same depth, wherein the first sub-layer of the second electric-conduction layer and the first sub-layer of the second electric-conduction connecting layer couple the second pad layer with a first portion of the lower electric-conduction layer..Iaddend.

.Iadd.32. The IC device according to claim 31, further comprising: a third electric-conduction layer, comprised of a first and second sub-layers at the same depth, a third electric-conduction connecting layer, comprised of a first and second sub-layers at the same depth; wherein the second sub-layer of the third electric-conduction layer and the second sub-layer of the third electric-conduction connecting layer couple a third pad layer with a second portion of the lower electric-conduction layer..Iaddend.

.Iadd.33. The IC device according to claim 31, wherein the second pad layer is designated to be coupled to a ground potential..Iaddend.

.Iadd.34. The IC device according to claim 31, wherein the second pad layer is designated to be coupled to a voltage potential..Iaddend.

.Iadd.35. The IC device according to claim 31, wherein the first pad layer is designated to be coupled to a high frequency signal..Iaddend.

.Iadd.36. The IC device according to claim 29, wherein the compound layer structure and the lower electric-conduction layer are spaced apart by at least one electric-conduction layer and at least one connecting layer..Iaddend.

.Iadd.37. The IC device according to claim 36, further comprising multiple second electric-conduction layers, multiple second electric-conduction connecting layers, multiple third electric-conduction layers, multiple third electric-conduction connecting layers; wherein the multiple second electric-conduction layers and the multiple second electric-conduction connecting layers are used to couple the second pad layer with one side of the lower electric-conduction layer, and the multiple third electric-conduction layers and the multiple third electric-conduction connecting layers are used to couple the other second pad layer with the other side of the lower electric-conduction layer..Iaddend.

.Iadd.38. The IC device according to claim 37, wherein the multiple second electric-conduction layers, multiple second electric-conduction connecting layers, multiple third electric-conduction layers, multiple third electric-conduction connecting layers and the lower electric-conduction layer are formed as a U-shaped structure..Iaddend.

.Iadd.39. The IC device according to claim 38, further comprising a passivation layer formed on the insulation layer, wherein the bonding zone of the passivation layer is smaller than the area of first and second pad layers..Iaddend.

.Iadd.40. The IC device according to claim 39, wherein the second pad layer and the other second pad layer are coupled to a power source..Iaddend.

.Iadd.41. The IC device according to claim 10, wherein the noise from the substrate is generated by an integrated circuit..Iaddend.

.Iadd.42. The IC device according to claim 10, further comprising multiple second electric-conduction layers, multiple second electric-conduction connecting layers, multiple third electric-conduction layers, multiple third electric-conduction connecting layers; wherein the multiple second electric-conduction layers and the multiple second electric-conduction connecting layers are used to couple the second pad layer with one side of the lower electric-conduction layer, and the multiple third electric-conduction layers and the multiple third electric-conduction connecting layers are used to couple the other second pad layer with the other side of the lower electric-conduction layer..Iaddend.

.Iadd.43. The IC device according to claim 42, wherein the multiple second electric-conduction layers, multiple second electric-conduction connecting layers, multiple third electric-conduction layers, multiple third electric-conduction connecting layers and the lower electric-conduction layer are formed as a U-shaped structure..Iaddend.

.Iadd.44. The IC device according to claim 10, wherein first pad layer is designated to be coupled to a high frequency signal and the second pad layer is designated to be coupled to a voltage potential or ground potential..Iaddend.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a cross-sectional diagram for the IC device disclosed in the U.S. Pat. No. 4,636,832.

(2) FIG. 2 is a cross-sectional diagram for the IC device disclosed in the U.S. Pat. No. 5,248,903.

(3) FIG. 3 is a cross-sectional diagram for the IC device disclosed in the U.S. Pat. No. 5,502,337.

(4) FIG. 4 is an upper side view for the structural illustration of a preferable embodiment of the IC pad according to the invention.

(5) FIG. 5 is a cross-sectional view along the A-A line cutting through FIG. 4 illustrating the preferable embodiment of the IC pad according to the invention.

(6) FIG. 6 is a flowchart illustrating the preferable embodiment of the method forming the IC pad according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(7) For your esteemed member of reviewing committee to further recognize and understand the characteristics, objectives, and functions of the present invention, a detailed description together with corresponding drawings are presented thereinafter.

(8) The invention discloses a structure of IC pad and its forming method. Its embodiments are described according to referential drawings, in which similar referential numbers represent similar elements.

(9) Please refer to FIG. 4 and FIG. 5, which are structural illustrations for the preferable embodiments of the IC pad according to the present invention. The IC pad structure includes a lower electric-conduction layer 300, a compound layer structure 100, and a first pad layer 600. The lower electric-conduction layer 300 formed at an appropriate position in the insulation layer 500 is coupled with plural electric-conduction layers 202 and plural electric-conduction connecting layers 201, shown in FIG. 5, such that the lower electric-conduction layer 300 may a voltage signal from a second pad layer 700 formed on the upper surface exposing on the insulation layer 500 through provide electric-conduction layers 202 and electric-conduction connecting layers 201 shown in FIG. 5, which further provides a connection to a device providing the voltage signal (not shown in the drawings). The second pad layer 700 further forms a bonding zone with a chip passivation layer 205 and 105. The noise transferred from the substrate .[.40.]. .Iadd.400 .Iaddend.will be kept away by the lower electric-conduction layer 300 which may be connected to a power source or voltage signal by the second pad layer 700.

(10) The compound layer structure 100 is arranged on the insulation layer 500 and is composed of at least one electric-conduction layer 102 and at least one electric-conduction connecting layer 101, both which are inter-overlapped to each other. The pad layer 600 is arranged on the compound layer structure 100 and is adjacent to the top face side of the insulation layer 500. In the preferable embodiments according to the invention and in order to lower down the value of the effective capacitance of the entire pad, the pad layer 600 is realized by the structuring method of polygon shape and the area of the electric-conduction layer 102 is designed to be smaller than that of the pad layer 600, such that the value of the equivalent electric capacitance to the lower electric-conduction layer 300 may be further effectively lowered down. The electric-conduction layer 102 may be realized by the methods of railing structure or honeycomb structure that may reduce the area of electric-conduction layer 102. The electric-conduction connecting layer 101 further includes plural vias and plural via plugs. The structure of this electric-conduction connecting layer 101 may be modified and implemented by those who are skilled in such art according to above disclosure, but it still possesses the merits of the invention and is also within the spirit and scope of the invention, so repetitious description is not presented herein.

(11) In the preferable embodiments according to the invention, the IC pad structure further includes a passivation layer 105, which is arranged on the insulation layer 500 and is partially connected to the pad layer 600. From above design, the compound layer structure 100 is signally connected and structured to the pad layer 600, and a steady bonding zone is thereby formed, such that it may enhance the boding tension and effectively raise the bonding adherence. Therefore, the tension generated during the bonding procedure to draw the entire structure of the IC pad out of the semiconductor chip may be prevented.

(12) In order to further recognize and understand the characteristics, objectives and functions of the present invention, please refer to FIG. 6, which is a flowchart illustrating the preferable embodiment of the method forming the IC pad according to the invention, wherein the numbers 91, 92, 93, 94 and 95 shown in the drawing respectively illustrate the steps from (a) to (e) of the method forming the IC pad according to the invention.

(13) Step (a): providing a substrate that is arranged with an insulation layer thereon.

(14) Step (b): forming a lower electric-conduction layer at an appropriate position in the insulation layer; the lower electric-conduction layer is composed of plural electric-conduction layers and plural electric-conduction connecting layers. In this embodiment, each of the electric-conduction layer is interlaced-connected to the corresponding electric-conduction connecting layers, as shown in FIG. 5, such that a signal connection may be provided to a bond-pad electric-connection layer, which further forms a bonding zone with a passivation layer, such that the pad layer may be connected to a potential of cleaner power source or electric potential.

(15) Step (c): a compound layer structure formed on the insulation layer is composed of at least one electric-conduction layer and at least one electric-conduction connecting layer, each of the electric-conduction layer is interlaced-connected to the corresponding electric-conduction connecting layers, as shown in FIG. 5, and the area of the electric-conduction layer can be reduced by the methods of railing structure or honeycomb structure, and the electric-conduction connecting layer further includes the structure of plural vias and plural via plugs.

(16) Step (d): forming a pad layer on the compound layer structure, wherein the area of the former is larger than that of the electric-conduction layer of the latter, and the pad layer is structured as a polygon shape.

(17) Step (e): forming a passivation layer on the insulation layer, such that the pad layer may form a bonding zone with the passivation layer.

(18) Accordingly, the structure of an IC pad and its forming method according to the invention may indeed reduce the value of equivalent electric capacitance of the entire pad, separate the noise coming from the semiconductor substrate, and increase the bonding adherence, so this kind of designing method may be adapted to integrated circuit of high frequency and fulfill the requirement of high frequency and low noise.