# Patent

## Title
Method of forming top electrode for capacitor and interconnection in integrated passive device (IPD)

## Abstract

A method of manufacturing a semiconductor device includes providing a substrate having a first conductive layer disposed on a top surface of the substrate. A high resistivity layer is formed over the substrate and the first conductive layer. A dielectric layer is deposited over the substrate, first conductive layer and high resistivity layer. A portion of the dielectric layer, high resistivity layer, and first conductive layer forms a capacitor stack. A first passivation layer is formed over the dielectric layer. A second conductive layer is formed over the capacitor stack and a portion of the first passivation layer. A first opening is etched in the dielectric layer to expose a surface of the high resistivity layer. A third and fourth conductive layer is deposited over the first opening in the dielectric layer and a portion of the first passivation layer.

## Background
CLAIM TO DOMESTIC PRIORITY
The present application is a division of, claims priority to, and fully incorporates herein by reference U.S. patent application Ser. No. 11/689,319, filed Mar. 21, 2007, and claims priority to the foregoing parent application pursuant to 35 U.S.C. §120.


FIELD OF THE INVENTION
The present invention relates in general to semiconductor devices and, more particularly, to an apparatus and method of fabricating a capacitor device and interconnection structures in an integrated passive device (IPD).
BACKGROUND OF THE INVENTION
Semiconductors, or computer chips, are found in virtually every electrical product manufactured today. Chips are used not only in very sophisticated industrial and commercial electronic equipment, but also in many household and consumer items such as televisions, clothes washers and dryers, radios, and telephones. As products become smaller but more functional, there is a need to include more chips in the smaller products to perform the functionality. The reduction in size of cellular telephones is one example of how more and more capabilities are incorporated into smaller and smaller electronic products.
As electrical devices become increasingly miniaturized, technologies have combined integrated circuit (IC) manufacturing techniques with traditional electrical circuit components to form such components as capacitors, resistors, filters, and interconnects directly upon a silicon or silicon-like substrate. For example, most of the devices in today's portable wireless products are passive components, and the integration of passive components into a substrate or a separate device can provide significant performance, cost, and size advantages.
A typical such semiconductor device 10 having an integrated capacitor device is shown in FIG. 1. A process for fabricating device 10 is depicted in FIGS. 2A-2I. Device 10 includes a substrate 12 and a first conductive layer 14 disposed over the substrate (FIG. 2A). A high resistivity layer 16 is disposed over a portion of the substrate 12 and first conductive layer 14 as shown (FIG. 2B). A dielectric layer 18 is disposed over the high resistivity layers (FIG. 2C).
As a next step, a second conductive layer 22 is formed over the dielectric layer 18. A wire bond (WB) pad 20 is formed on the substrate (FIG. 2D). A first passivation layer 24 is formed as shown (FIG. 2E). A third and fourth conductive layer 26 and 28 are then disposed over the passivation layer 24 as shown (FIG. 2F). A second passivation layer 30 is then formed over the layers 26 and 28 (FIG. 2G). Fifth and sixth conductive layers 32 and 34 are formed (FIG. 2H). A solder bump 36 is then deposited on the layer 34 (FIG. 2I).
In the depicted process, the second conductive layer 22 is used as a top electrode of the capacitor device, which is patterned before the deposition of the first passivation layer 24. A wet etching process is used for patterning the layer 22. The wet etching process is generally not uniform, making critical dimension (CD) control a potentially serious manufacturing issue when patterning layer 22.
As a result, a lack of uniformity and potential over/under etching will effect the capacitance characteristics of the capacitor device, resulting in non-uniform specifications of the capacitor device. The center frequency of a filter having such a capacitor device is necessarily affected.
SUMMARY OF THE INVENTION
A need exists for a method of forming a semiconductor device having an integrated capacitor device with better controlled capacitance and corresponding increased uniformity and repeatability. In addition, a need exists for manufacturing techniques for the semiconductor device as described which reduce process steps, resulting in shorter cycle time and lower cost.
In one embodiment, the present invention is a semiconductor device comprising a substrate and first conductive layer formed over a surface of the substrate. A resistive layer is formed over the substrate and first conductive layer. A dielectric layer is formed over the substrate, first conductive layer and resistive layer. A first passivation layer is formed over the dielectric layer and substrate. A first opening is formed through the first passivation to expose the dielectric layer and a second opening is formed through the first passivation layer and dielectric layer to expose the resistive layer and first conductive layer. A second conductive layer is formed over the exposed dielectric layer. A portion of the first conductive layer, resistive layer, dielectric layer, and second conductive layer constitute a metal-insulator-metal capacitor. A third conductive layer is formed in the first opening over the second conductive layer and further formed in the second opening over the exposed resistive layer and the exposed first conductive layer. A fourth conductive layer is formed over the third conductive layer. A second passivation layer is formed over the fourth conductive layer and first passivation layer.
In another embodiment, the present invention is a semiconductor device comprising a substrate and first conductive layer formed over the substrate. A resistive layer is formed over the substrate and first conductive layer. A dielectric layer is formed over the resistive layer. A first passivation layer is formed over the dielectric layer and substrate. A portion of the first passivation is removed to expose the dielectric layer and a portion of the first passivation layer and dielectric layer is removed to expose the resistive layer. A second conductive layer is formed over the exposed dielectric layer. A third conductive layer is formed over the second conductive layer and the exposed resistive layer. A fourth conductive layer is formed over the third conductive layer. A second passivation layer is formed over the fourth conductive layer and first passivation layer.
In another embodiment, the present invention is a semiconductor device comprising a substrate and first conductive layer formed over the substrate. A resistive layer is formed over the substrate. A dielectric layer is formed over the resistive layer. A first passivation layer is formed over the dielectric layer and substrate. A portion of the first passivation is removed to expose the dielectric layer and a portion of the first passivation layer and dielectric layer is removed to expose the resistive layer. A second conductive layer is formed over the exposed dielectric layer. A third conductive layer is formed over the second conductive layer and the exposed resistive layer.
In another embodiment, the present invention is a semiconductor device comprising a substrate and first conductive layer formed over the substrate. A resistive layer is formed over the first conductive layer. A dielectric layer is formed over the resistive layer. A first passivation layer is formed over the dielectric layer and substrate. A portion of the first passivation is removed to expose the dielectric layer and an opening is formed through the first passivation layer and dielectric layer to expose the resistive layer. A second conductive layer is formed over the exposed dielectric layer.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates an example prior art semiconductor device;
FIG. 2A illustrates a first step in an example prior art method of manufacturing an embodiment of a semiconductor device;
FIG. 2B illustrates a second step in the prior art method of manufacturing began with FIG. 2A;
FIG. 2C illustrates a third step in the prior art method of manufacturing began with FIG. 2A;
FIG. 2D illustrates a fourth step in the prior art method of manufacturing began with FIG. 2A;
FIG. 2E illustrates a fifth step in the prior art method of manufacturing began with FIG. 2A;
FIG. 2F illustrates a sixth step in the prior art method of manufacturing began with FIG. 2A;
FIG. 2G illustrates a seventh step in the prior art method of manufacturing began with FIG. 2A;
FIG. 2H illustrates an eighth step in the prior art method of manufacturing began with FIG. 2A;
FIG. 2I illustrates a final, ninth step in the prior art method of manufacturing began with FIG. 2A;
FIG. 3 illustrates an example first embodiment of a semiconductor device;
FIG. 4A illustrates a first step in an example method of manufacturing a semiconductor device;
FIG. 4B illustrates a second step in an example method of manufacturing a semiconductor device;
FIG. 4C illustrates a third step in an example method of manufacturing a semiconductor device;
FIG. 4D illustrates a fourth step in an example method of manufacturing a semiconductor device;
FIG. 4E illustrates a fifth step in an example method of manufacturing a semiconductor device;
FIG. 4F illustrates a sixth step in an example method of manufacturing a semiconductor device;
FIG. 4G illustrates a seventh step in an example method of manufacturing a semiconductor device;
FIG. 4H illustrates an eighth step in an example method of manufacturing a semiconductor device;
FIG. 4I illustrates a final, ninth step in an example method of manufacturing a semiconductor device;
FIG. 5A illustrates an example second embodiment of a semiconductor device; and
FIG. 5B illustrates a top view of an embodiment of a semiconductor device.



DETAILED DESCRIPTION OF THE DRAWINGS
The present invention is described in one or more embodiments in the following description with reference to the Figures, in which like numerals represent the same or similar elements. While the invention is described in terms of the best mode for achieving the invention's objectives, it will be appreciated by those skilled in the art that it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims and their equivalents as supported by the following disclosure and drawings.
A semiconductor device having an integrated passive capacitor device can be manufactured which serves to alleviate the problem of non-uniformity in dimension, and better controlled capacitance, resulting in overall higher repeatability. Moreover, the semiconductor device can be manufactured using less process steps, which contributes to shorter cycle time and lower overall cost. In addition, a lithography step is eliminated in the manufacturing process, which reduces overall cost even further.
Passive devices such as a capacitor device, which will be further described in detail, can be combined with other passive devices, such as resistors, transceivers, receivers, BALUNs, and filter devices to constitute the semiconductor device. In one embodiment, a capacitor device can be interconnected with an inductor device as will be later described. A variety of passive components can be interconnected, however, to suit a particular application.
Turning to FIG. 3, a semiconductor device 100 manufactured according to various aspects of the present invention is illustrated. Device 100 includes a substrate 102, over which a first conductive layer 104 is disposed. A WB pad 106 is also optionally disposed over the substrate 102 as shown. A high resistivity layer 108 is disposed above the first conductive layer 104 and a portion of the center of the substrate 102 as shown. A dielectric layer 110 is formed above the high resistivity layer 108. A first passivation layer 112 is disposed above the dielectric layer.
In a departure from the prior art, a thin, second conductive layer 114 is deposited and patterned after the passivation layer 112 has been formed. Layer 114 serves as a top electrode of a capacitor device. A third and fourth conductive layer 118, 120 are formed over the electrode 114. A second passivation layer 122 is formed over the foregoing components. An opening is maintained to expose the fourth conductive layer for electrical connectivity. In one embodiment, the dielectric layer 110 above the WB pad 106 is etched to expose a surface 124 of the WB pad for electrical connectivity. Fifth and sixth conductive layers 126 and 128 are disposed above the opening. Finally, a bump 130 is connected to the layer 128.
Semiconductor device 100 has several features which innovate over the prior art device 10, including the patterning of a thin conductive layer 114 after the deposition of the first passivation layer 112. In addition, the dielectric layer 110 can be patterned with the first passivation layer as a hard mask. This patterning can occur after the second conductive layer 114 is deposited, which cuts out a fabrication step and lowers cost. A dimension of the top capacitor electrode 114 can be defined by the design and/or lithography of the thin first passivation layer 112. By using the passivation layer 112, the top electrode 114 is prevented from being over-etched. The patterning of the first passivation layer 112 is generally better controlled than the second conductive layer 114 patterning with prior art wet etching as only lithography is involved to define the size of the top electrode 114.
The respective lithography of the dielectric layer 110 having positive resist can be removed after using the first passivation layer 112 as the hard mask, which saves fabrication cost. In addition, conductive layer 114 can be made optional if tolerances of capacitances are not limited for a particular application.
Turning to FIG. 4A a first step in an example method of manufacturing a semiconductor device 100 is depicted in accordance with the present invention. A substrate 102 is provided. A first conductive layer 104 is deposited and patterned. The materials used in the layer 104 can include aluminum (Al), aluminum alloys, copper (Cu), gold (Au), silicide and polysilicon materials. An optional WB pad 106 is also disposed over the substrate 102.
FIG. 4B shows the deposition and patterning of a high resistivity layer 108, which is disposed over the layer 104 and a portion of the substrate 102 as shown. The high resistivity layer can be nickel-chromium (Ni—Cr), polysilicon, and other materials having a high resistance.
FIG. 4C illustrates the deposition of a dielectric layer 110 over the high resistivity layer 108, conductive layer 104, and substrate 102 as shown. The dielectric layer can be composed of such materials as silicon nitride (SiN), tantalum oxide (Ta2O5), hafnium oxide (HfO2), or a dielectric film material. The dielectric layer 110, high resistivity layer 108, and conductive layer 104 form various subcomponents of a capacitor stack.
FIG. 4D illustrates the forming of a first passivation layer 112 which is patterned and formed as shown over the layer 110. The passivation layer 112 can include an insulation material including polyimide, benzocyclobutene (BCB), or lead oxide (PbO).
FIG. 4E illustrates the deposition and patterning of a thin, second conductive layer 114 which is deposited over the capacitor stack as shown. Again, the deposition of layer 114 occurs after the patterning and deposition of the passivation layer 112. The patterning of layer 114 over the depicted WB pad 106 is optional. Materials such as aluminum (Al) and aluminum alloys can be used. Layer 114 becomes the top electrode of a capacitor device integrated into device 110.
The first passivation layer 112 is then used as the hard mask to etch the dielectric layer 110 as shown in FIG. 4F, which saves in production costs and fabrication steps.
FIG. 4G illustrates the deposition and patterning of a third and fourth conductive layer 118 and 120 which are formed over the layer 114 and elsewhere as depicted. The layer 118 can include such materials as titanium (Ti), titanium tungsten (TiW), chromium (Cr), tantalum (Ta), and tantalum nitride (TaN). The layer 120 can include such materials as aluminum (AL), aluminum alloy, copper (Cu), and gold (Au). An opening 116 exposes a surface of the dielectric layer 110 as shown.
FIG. 4H illustrates the deposition and patterning of a second passivation layer 122. Again, the passivation layer can include an insulation material including polyimide, benzocyclobutene (BCB), or lead oxide (PbO). Layer 122 can terminate on the first passivation layer 112 or the layer 122 can terminate on the WB pad 106. An opening 123 is formed in the passivation layer 122 to expose a surface of the conductive layer 120 and provide electrical connectivity.
Dielectric layer 110 over the WB pad 106 can be etched after completing the second passivation layer 122 to expose a surface of the WB pad 106 via opening 124 to suit a particular application as shown in FIG. 4I. As a next step, fifth and sixth conductive layers 126 and 128 are deposited over the opening 123 to provide electrical connectivity. The fifth conductive layer 126 can include such materials as titanium (Ti), titanium tungsten (TiW), aluminum (Al), aluminum alloy, and chromium (Cr). The sixth conductive layer 128 can include such materials as copper, copper/nickel vanadate (cu/NiV), gold/nickel (Au/Ni), and chromium/copper/copper (CrCu/Cu).
A bump 130, which can include a solder bump, gold (Au) bump, or copper (Cu) pillar structures is then formed over the layer 128 as shown. In one embodiment, the WB pad 106 can be protected during solder reflow, flux stripping, or other chemical processes.
Turning to FIG. 5A, a second embodiment of a semiconductor device 100 is shown. Device 100 again includes a substrate 102. A first metal layer 104 is disposed over the substrate 102. The first metal layer can include an aluminum-copper (AlCu) material.
A WB pad 106 is disposed above the substrate as shown. A high resistivity layer 108 is disposed above a portion of the substrate 102 and metal layer 104. The layer 108 can include a tantalum silicide (TaSi) material. A dielectric layer 110 is disposed above the layers 108, 106, and 104. The dielectric layer can include a silicon nitride (Si3N4) material.
A first passivation layer 112 such as a polyimide material is deposed as shown. The layer 112 is patterned to leave an opening to expose a surface of the dielectric layer 110 in order to receive a thin, second metal layer 114 is shown. Again, layer 114 is deposited over a capacitor stack. Layer 114 can include an aluminum-copper (Al—Cu) material.
Again, in a departure from the prior art, the layer 114 is deposited and patterned after the polyimide layer 112 is cured. Layer 114 serves as the top electrode of the capacitor device and is only patterned on the capacitor top plate, accordingly. Layer 114 is used partially to avoid any ion milling on the deposited dielectric layer 110.
Again, in a departure from the prior art, the dielectric layer 110 is patterned with the polyimide layer 112 as a hard mask after the second metal layer 114 is patterned. Such an approach again serves to eliminate a fabrication step and provides efficiency in manufacturing.
A third metal layer 118 and a fourth metal layer 120 are deposited. In one embodiment, titanium (Ti) can be incorporated into the layer 118 and copper (Cu) can be incorporated into the layer 120. A second polyimide layer 122 is formed as shown, leaving an opening to receive fifth and sixth conductive layers 126 and 128. Layer 126 can be composed of a titanium (Ti) material. Layer 128 can be composed of a nickel vanadium (NiV)/copper (Cu) material, respectively.
Layer 110 can be again etched to leave an opening 124 to expose a surface of the WB pad 106. A bump 130 is formed over layer 128 as shown to provide electrical connectivity.
FIG. 5B illustrates a top view of a semiconductor device 100 as depicted in FIG. 5A. Again, such structures as bump 130, layers 122 and 120 are shown. The depicted passive spiral inductor device 132 includes a portion of metal layer 120 which has been patterned in a spiral shape. In the depicted embodiment, a nitride such as silicon nitride (SiN) is not found underneath the inductor device 132, except for the bridge portion 134, so as not to affect the performance of the inductor device 132.
Semiconductor devices 100 in the various embodiments shown can be manufactured using tools and equipment commonly known in the art, such as wire bonding, patterning, etching and similar equipment. Devices 100 serve to continue to advance integrated passive device technology at reduced fabrication cost, while resulting in larger overall repeatable quality.
While one or more embodiments of the present invention have been illustrated in detail, the skilled artisan will appreciate that modifications and adaptations to those embodiments may be made without departing from the scope of the present invention as set forth in the following claims.

## Claims

1. A semiconductor device, comprising:
a substrate;
a first conductive layer formed over a surface of the substrate;
a resistive layer formed over the substrate and first conductive layer;
a dielectric layer formed over the substrate, first conductive layer and resistive layer;
a first passivation layer formed over the dielectric layer and substrate, wherein a first opening is formed through the first passivation layer to expose the dielectric layer and a plurality of second openings is formed through the first passivation layer and dielectric layer to expose the resistive layer and first conductive layer;
a second conductive layer formed in the first opening in contact with the exposed dielectric layer and sidewalls of the first opening, wherein a portion of the first conductive layer, resistive layer, dielectric layer, and second conductive layer constitutes a metal-insulator-metal capacitor;
a third conductive layer formed in the first opening over the second conductive layer and further formed in the second openings over the exposed resistive layer and the exposed first conductive layer;
a fourth conductive layer formed over the third conductive layer; and
a second passivation layer formed over the fourth conductive layer and first passivation layer.

2. The semiconductor device of claim 1, further including:
a fifth conductive layer formed over the fourth conductive layer; and
a sixth conductive layer formed over the fifth conductive layer.

3. The semiconductor device of claim 2, wherein the fifth and sixth conductive layers constitute an under-bump metallization.

4. The semiconductor device of claim 2, further including an electrical interconnect formed over the sixth conductive layer.

5. The semiconductor device of claim 4, wherein the electrical interconnect includes a bump or conductive pillar.

6. The semiconductor device of claim 1, further including a wire-bond pad formed over the substrate.

7. A semiconductor device, comprising:
a substrate;
a first conductive layer formed over the substrate;
a resistive layer formed over the substrate and first conductive layer;
a dielectric layer formed over the resistive layer;
a first passivation layer formed over the dielectric layer and substrate, wherein a portion of the first passivation layer is removed to expose the dielectric layer and a portion of the first passivation layer and dielectric layer is removed to expose the resistive layer;
a second conductive layer formed in contact with the exposed dielectric layer and sidewalls of the removed portion of the first passivation layer;
a third conductive layer formed over the second conductive layer and the exposed resistive layer;
a fourth conductive layer formed over the third conductive layer; and
a second passivation layer formed over the fourth conductive layer and first passivation layer.

8. The semiconductor device of claim 7, wherein a portion of the first conductive layer, resistive layer, dielectric layer, and second conductive layer constitutes a metal-insulator-metal capacitor.

9. The semiconductor device of claim 7, further including:
a fifth conductive layer formed over the fourth conductive layer; and
a sixth conductive layer formed over the fifth conductive layer.

10. The semiconductor device of claim 9, wherein the fifth and sixth conductive layers constitute an under-bump metallization.

11. The semiconductor device of claim 9, further including an electrical interconnect formed over the sixth conductive layer.

12. The semiconductor device of claim 11, wherein the electrical interconnect includes a bump or conductive pillar.

13. The semiconductor device of claim 7, further including a wire-bond pad formed over the substrate.

14. A semiconductor device, comprising:
a substrate;
a first conductive layer formed over the substrate;
a resistive layer formed over the substrate;
a dielectric layer formed over the resistive layer;
a first passivation layer formed over the dielectric layer and substrate, wherein a portion of the first passivation layer is removed to expose the dielectric layer and a portion of the first passivation layer and dielectric layer is removed to expose the resistive layer;
a second conductive layer formed over the exposed dielectric layer and sidewalls of the removed portion of the first passivation layer; and
a third conductive layer formed over the second conductive layer and the exposed resistive layer.

15. The semiconductor device of claim 14, wherein a portion of the first conductive layer, resistive layer, dielectric layer, and second conductive layer constitutes a metal-insulator-metal capacitor.

16. The semiconductor device of claim 14, further including:
a fourth conductive layer formed over the third conductive layer; and
a second passivation layer formed over the fourth conductive layer and first passivation layer.

17. The semiconductor device of claim 16, further including:
a fifth conductive layer formed over the fourth conductive layer; and
a sixth conductive layer formed over the fifth conductive layer.

18. The semiconductor device of claim 17, wherein the fifth and sixth conductive layers constitute an under-bump metallization.

19. The semiconductor device of claim 17, further including an electrical interconnect formed over the sixth conductive layer.

20. The semiconductor device of claim 19, wherein the electrical interconnect includes a bump or conductive pillar.

21. A semiconductor device, comprising:
a substrate;
a first conductive layer formed over the substrate;
a resistive layer formed over the first conductive layer;
a dielectric layer formed over the resistive layer;
a first passivation layer formed over the dielectric layer and substrate, wherein a portion of the first passivation layer is removed to expose the dielectric layer and an opening is formed through the first passivation layer and dielectric layer to expose the resistive layer; and
a second conductive layer formed through the first passivation layer to contact the exposed dielectric layer.

22. The semiconductor device of claim 21, wherein a portion of the first conductive layer, resistive layer, dielectric layer, and second conductive layer constitutes a metal-insulator-metal capacitor.

23. The semiconductor device of claim 21, further including:
a third conductive layer formed over the second conductive layer and the exposed resistive layer;
a fourth conductive layer formed over the third conductive layer; and
a second passivation layer formed over the fourth conductive layer and first passivation layer.

24. The semiconductor device of claim 23, further including:
a fifth conductive layer formed over the fourth conductive layer; and
a sixth conductive layer formed over the fifth conductive layer.

25. The semiconductor device of claim 24, further including an electrical interconnect formed over the sixth conductive layer.