US5370766A
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US
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Methods for fabrication of thin film inductors, inductor networks and integration with other passive and active devices
Assignee: Semiconductor Components Industries LLC
•
Filing: 1993-08-16
•
Granted: 1994-12-06
•
Expires: 2013-08-16
Abstract
Abstract The fabrication of thin film inductors on a substrate, which may include thin film resistors, thin film capacitors, and semiconductor devices. In one embodiment an inductor is fabricated initially on a substrate and then integrated with other devices subsequently formed on the substrate. In this embodiment, process steps used to fabricate such other devices utilize temperatures sufficiently low to prevent damaging or destroying the characteristics of the inductor. In another embodiment the fabrication of an inductor is achieved through photoresist masking and plating techniques. In alternative embodiments, fabrication of an inductor is achieved by sputtering, photoresist processes and etching/ion-milling techniques. A combination of various individual process steps from various embodiments are suitable for use to fabricate the individual layers to achieve a structure of this invention. The inductor fabricated in accordance with this invention is connected to other passive or active components through metal interconnections in order to improve the frequency performance of the inductor. In certain embodiments, parasitic capacitance of the inductor is significantly reduced by fabricating inductor coils on dielectric bridges. In certain embodiments, a magnetic core of ferromagnetic material is used to improve the performance of the inductor at frequencies below about 100 MHz.
Inventors
- 👤 Chan M. Desaigoudar
- 👤 Suren Gupta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:29
CPC Classifications
H; H10; H10D; H10D84/00; H10W; H10W20/00; H10W20/40; H10W20/497; H01; H01F; H01F17/00; H01F17/0006; H01F2017/0046; H01F2017/008; H05; H05K; H05K1/00; H05K1/16; H05K3/00; H05K3/46; H05K3/4644; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49099
Claims Analysis
Total Claims: 111
Claim 1
Independent Claim
77 words
A method for fabricating an electronic device comprising the steps of: utilizing a substrate having a first and a second surface; forming a first conductive layer above said first surface of said substrate; forming a patterned dielectric layer above said first conductive layer; and forming a patterned thin film conductor above said patterned dielectric layer in a pattern to provide an inductor having a desired inductance value and which makes electrical contact with said first conductive layer.
Claim 2
Independent Claim
77 words
A method for fabricating an electronic device comprising the steps of: utilizing a substrate having a first and a second surface; forming a first conductive layer above said first surface of said substrate; forming a patterned dielectric layer above said first conductive layer; and forming a patterned thin film conductor above said patterned dielectric layer in a pattern to provide an inductor having a desired inductance value and which makes electrical contact with said first conductive layer.
Claim 3
Dependent Claim
42 words
A method as in claim 1 wherein said substrate comprises a conductive or semiconductive material, and which further comprises the step of forming an insulating layer above said first surface of said substrate, thereby insulating said first conductive layer from said substrate.
Claim 4
Dependent Claim
21 words
A method as in claim 2 wherein said substrate comprises silicon, Al 2 O 3 -TiC, or a conductive ferromagnetic material.
Claim 5
Dependent Claim
38 words
A method as in claim 2 which further comprises the step of forming vias in said layer of insulation to allow electrical connection between said substrate and one or both of said conductive layer and thin film conductor.
Claim 6
Dependent Claim
13 words
A method as in claim 1 wherein said substrate comprises an insulating substrate.
Claim 7
Dependent Claim
31 words
A method as in claim 2 wherein said substrate comprises a semiconductive material and which method further comprises the step of forming one or more semiconductor devices in said semiconductive substrate.
Claim 8
Dependent Claim
19 words
A method as in claim 6 wherein said inductor is formed adjacent to said one or more semiconductor devices.
Claim 9
Dependent Claim
18 words
A method as in claim 6 wherein said inductor is formed above said one or more semiconductor devices.
Claim 10
Dependent Claim
19 words
A method as in claim 6 wherein said semiconductor devices are formed on said second surface of said substrate.
Claim 11
Dependent Claim
31 words
A method as in claim 1 which further comprises the steps of fabricating one or more devices, selected from the group consisting of thin film resistors and capacitors, on said substrate.
Claim 12
Dependent Claim
22 words
A method as in claim 10 wherein said inductor is formed above one or more of said thin film resistors and capacitors.
Claim 13
Dependent Claim
22 words
A method as in claim 10 wherein said inductor is formed adjacent one or more of said thin film resistors and capacitors.
Claim 14
Dependent Claim
43 words
A method as in claim 10 wherein said substrate comprises semiconductor material containing one or more semiconductor devices and in which said one or more inductors, resistors, and capacitors are fabricated above at least one of said one or more of semiconductor devices.
Claim 15
Dependent Claim
24 words
A method as in claim 1 which further comprises the step of forming a core material on at least one side of said inductor.
Claim 16
Dependent Claim
24 words
A method as in claim 1 which further comprises the step of forming a core material on both top and bottom of said inductor.
Claim 17
Dependent Claim
18 words
A method as in claim 14 wherein said core material comprises iron, NiFe, sandust, or a ferromagnetic material.
Claim 18
Dependent Claim
18 words
A method as in claim 15 wherein said core material comprises iron, NiFe, sandust, or a ferromagnetic material.
Claim 19
Dependent Claim
47 words
A method as in claim 1 which further comprises the step of forming a set of studs for the formation of said patterned thin film conductor such that said patterned thin film conductor is supported by said studs and, between said studs, is separated from underlying layers.
Claim 20
Dependent Claim
28 words
A method as in claim 18 which further comprises the step of forming a clamping layer on said conductive layer to attach said conductive later to said studs.
Claim 21
Dependent Claim
22 words
A method as in claim 19 which further comprises the step of forming a passivation layer on the surface of the device.
Claim 22
Dependent Claim
18 words
A method as in claim 18 which further comprises the step of passivating said thin film with photoresist.
Claim 23
Dependent Claim
22 words
A method as in claim 1 wherein said first conductive layer comprises a resistive layer serving as one or more resistor devices.
Claim 24
Dependent Claim
31 words
A method as in claim 1 wherein said first conductive layer comprises a material selected from the group of materials consisting of aluminum, copper, silver, gold, polycrystalline silicon, and alloys thereof.
Claim 25
Dependent Claim
33 words
A method as in claim 1 which further comprises a step of forming a capacitor having said substrate serving as its first plate and said first conductive layer serving as its second plate.
Claim 26
Dependent Claim
20 words
A method as in claim 1 wherein said first conductive layer is patterned to form one or more electrical interconnects.
Claim 27
Dependent Claim
19 words
A method as in claim 25 wherein said first conductive layer also serves as one plate of a capacitor.
Claim 28
Dependent Claim
28 words
A method as in claim 1 wherein said first conductive layer comprises a resistive material selected from the group of materials consisting of TaN, nichrome, and polycrystalline silicon.
Claim 29
Dependent Claim
15 words
A method as in claim 5 wherein said substrate comprises glass, quartz, or ceramic material.
Claim 30
Dependent Claim
79 words
A method as in claim 6 wherein said step of forming said one or more semiconductor devices is performed prior to said step of forming a patterned dielectric layer above said first conductive layer and prior to said step of forming a patterned thin film conductor, wherein said step of forming a patterned dielectric layer and said step of forming a patterned thin film conductor are performed at sufficiently low temperatures to prevent a deterioration of said semiconductor devices.
Claim 31
Dependent Claim
31 words
A method as in claim 6 which further comprises the steps of fabricating one or more devices, selected from the group consisting of thin film resistors and capacitors, on said substrate.
Claim 32
Dependent Claim
22 words
A method as in claim 30 wherein said inductor is formed above one or more of said thin film resistors and capacitors.
Claim 33
Dependent Claim
22 words
A method as in claim 30 wherein said inductor is formed adjacent one or more of said thin film resistors and capacitors.
Claim 34
Dependent Claim
29 words
A method as in claim 30 wherein said substrate comprises semiconductor material and in which said one or more inductors, resistors, and capacitors are fabricated above said semiconductor devices.
Claim 35
Dependent Claim
20 words
A method as in claim 30 wherein said first conductive layer is patterned to form one or more electrical interconnects.
Claim 36
Dependent Claim
20 words
A method as in claim 10 wherein said first conductive layer is patterned to form one or more electrical interconnects.
Claim 37
Dependent Claim
20 words
A method as in claim 13 wherein said first conductive layer is patterned to form one or more electrical interconnects.
Claim 38
Independent Claim
65 words
A method for fabricating an electronic device utilizing a substrate comprising the steps of: forming a first patterned conductive layer above said substrate; forming a first patterned dielectric layer, exposing those areas of said first conductive layer to which electrical contact is to be made; and forming a second conductive layer on said first patterned dielectric layer in a pattern to form an inductor coil.
Claim 39
Independent Claim
65 words
A method for fabricating an electronic device utilizing a substrate comprising the steps of: forming a first patterned conductive layer above said substrate; forming a first patterned dielectric layer, exposing those areas of said first conductive layer to which electrical contact is to be made; and forming a second conductive layer on said first patterned dielectric layer in a pattern to form an inductor coil.
Claim 40
Dependent Claim
37 words
A method as in claim 37 wherein said substrate comprises a semiconductor or conductive material and wherein said method comprises the additional step of forming a base dielectric layer between said substrate and said first conductive layer.
Claim 41
Dependent Claim
43 words
A method as in the claim 38 wherein said step of forming said base dielectric layer comprises the step of forming said base dielectric layer in a pattern to expose those portions of said substrate to which electrical contact is to be made.
Claim 42
Dependent Claim
20 words
A method as in claim 37 wherein said substrate comprises glass, quartz, Al 2 O 3 /TiC, or ceramic materials.
Claim 43
Dependent Claim
16 words
A method as in claim 38 wherein said substrate comprises conductive ferromagnetic material or semiconductor material.
Claim 44
Dependent Claim
12 words
A method as in the claim 41 wherein said substrate comprises silicon.
Claim 45
Dependent Claim
20 words
A method as in claim 38 wherein said base dielectric layer comprises silicon dioxide of approximately 10,000 Å in thickness.
Claim 46
Dependent Claim
22 words
A method as in claim 37 wherein said first conductive layer comprises aluminum, copper, silver, gold, polycrystalline silicon, or an alloy thereof.
Claim 47
Dependent Claim
20 words
A method as in claim 44 wherein said first conductive layer is formed to a thickness of approximately 5,000 Å.
Claim 48
Dependent Claim
41 words
A method as in claim 37 wherein said first dielectric layer comprises one or more materials selected from the group of materials consisting of silicon dioxide and silicon nitride, formed to a thickness within the range of 2,000 to 10,000 Å.
Claim 49
Dependent Claim
28 words
A method as in claim 38 wherein said first dielectric layer comprises one or more materials selected from the group of materials consisting of silicon dioxide and silicon.
Claim 50
Dependent Claim
17 words
A method as in claim 38 wherein said base dielectric layer comprises a layer of baked photoresist.
Claim 51
Dependent Claim
24 words
A method as in claim 48 wherein said layer of baked photoresist is formed to a thickness within the range of approximately 1-5 microns.
Claim 52
Dependent Claim
36 words
A method as in claim 38 wherein said step of forming said base dielectric layer comprises the steps of: applying the photoresist material to the top surface of said device; and stabilizing said layer of photoresist.
Claim 53
Dependent Claim
15 words
A method as in claim 50 wherein said step of stabilizing comprises baking said photoresist.
Claim 54
Dependent Claim
32 words
A method as in claim 51 wherein said step of baking comprises baking within the range of approximately 200°-300° C. for approximately 6 to 12 hours in a vacuum or inert environment.
Claim 55
Dependent Claim
15 words
A method as in claim 50 wherein said step of stabilizing comprises polymerizing said photoresist.
Claim 56
Dependent Claim
17 words
A method as in claim 53 wherein said step of polymerizing is performed utilizing an electron beam.
Claim 57
Dependent Claim
20 words
A method as in claim 37 wherein said second conductive layer comprises aluminum, copper, silver, gold, or an alloy thereof.
Claim 58
Dependent Claim
105 words
A method as in claim 37 wherein said step of forming said second metallization layer comprising the steps of: forming a seed layer of conductive material on the surface of the device in a pattern resembling the desired pattern of the to-be-formed conductive layer; forming a layer of masking material on the surface of the device in a pattern to expose those portions of said seed layer where the inductor coil is to be formed; electroplating additional metal material to exposed portions of said seed layer; removing said masking layer; and removing those portions of said seed layer not covered by said additional conductive material.
Claim 59
Dependent Claim
24 words
A method as in claim 56 wherein said seed layer comprises TiW, Cu, Pd, Ti, Ni, Cr, Ag, Au, NiFe, or an alloy thereof.
Claim 60
Dependent Claim
38 words
A method as in claim 57 wherein said seed layer comprises a first layer of TiW formed to a thickness of approximately 200 Å and a second layer of copper formed to a thickness of approximately 1,000 Å.
Claim 61
Dependent Claim
20 words
A method as in claim 56 wherein said additional metal material comprises copper, silver, or gold, or an alloy thereof.
Claim 62
Dependent Claim
25 words
A method as in claim 56 wherein said additional metal material is formed to a thickness in the range of approximately 3 to 10 microns.
Claim 63
Dependent Claim
53 words
A method as in claim 37 wherein said step of forming said inductor coil comprises the steps of: forming a layer of metallization; forming a mask in a desired pattern to protect those portions of said metallization layer which are to form said inductor coil; and removing exposed portions of said metallization layer.
Claim 64
Dependent Claim
23 words
A method as in claim 37 which further comprises the step of forming a layer of passivation on the surface of the device.
Claim 65
Independent Claim
23 words
A method as in 62 wherein said step of forming a layer of passivation comprises the step of forming a layer of photoresist.
Claim 66
Independent Claim
23 words
A method as in 62 wherein said step of forming a layer of passivation comprises the step of forming a layer of photoresist.
Claim 67
Independent Claim
32 words
A method as in 63 wherein said step of forming a layer of photoresist comprises forming a layer of photoresist to a thickness within the range of approximately 1 to 5 microns.
Claim 68
Independent Claim
32 words
A method as in 63 wherein said step of forming a layer of photoresist comprises forming a layer of photoresist to a thickness within the range of approximately 1 to 5 microns.
Claim 69
Dependent Claim
17 words
A method as in claim 63 which further comprises the step of stabilizing said layer of photoresist.
Claim 70
Dependent Claim
22 words
A method as in claim 65 wherein said step of stabilizing said layer of photoresist comprises the step of baking said photoresist.
Claim 71
Dependent Claim
34 words
A method as in claim 66 wherein said step of baking comprises baking within the range of approximately 200° to 300° C. for approximately 6 to 12 hours in a vacuum or inert environment.
Claim 72
Dependent Claim
15 words
A method as in claim 65 wherein said step of stabilizing comprises polymerizing said photoresist.
Claim 73
Dependent Claim
17 words
A method as in claim 68 wherein said step of polymerizing is performed utilizing an electron beam.
Claim 74
Independent Claim
109 words
A method as in claims 37 wherein said step of forming a second conductive layer comprises the steps of: forming a second layer of dielectric on said first dielectric layer, in areas where support studs are to be formed; forming a third layer of dielectric material which is capable of being selectively etched with respect to said second layer of dielectric material; removing said third layer of said material from above said support studs; forming a patterned conductive layer above said second and third dielectric layers in a pattern defining an inductor coil; and removing at least portions of said third layer of dielectric material beneath said inductor coil.
Claim 75
Dependent Claim
38 words
A method as in claim 70 wherein said second layer of dielectric material comprises a durable photoresist and said third layer of dielectric material comprises a layer of photoresist less durable than said second layer of dielectric material.
Claim 76
Dependent Claim
32 words
A method as in claim 70 wherein said second layer material of dielectric material comprises material selected from the group of materials consisting of oxide, nitride, and Al 2 O 3 .
Claim 77
Dependent Claim
15 words
A method as in claim 72 wherein said third layer of dielectric material comprises photoresist.
Claim 78
Dependent Claim
41 words
A method as in claim 72 wherein said third layer of dielectric material comprises material selected from the group of materials consisting of oxide, nitride, and Al 2 O 3 other than the material used as said second layer of dielectric.
Claim 79
Dependent Claim
27 words
A method as in claim 72 wherein said second layer of dielectric material is formed to a thickness within the range of approximately 3 to 10 microns.
Claim 80
Dependent Claim
25 words
A method as in claim 72 wherein said third layer material is formed to a thickness from the range of approximately 2 to 10 microns.
Claim 81
Dependent Claim
35 words
A method as in claim 72 wherein said step of forming said third dielectric layer comprises the steps of: applying photoresist material to the top surface of said device; and stabilizing said layer of photoresist.
Claim 82
Independent Claim
15 words
A method as in claims 77 wherein said step of stabilizing comprises baking said photoresist.
Claim 83
Dependent Claim
27 words
A method as in claim 78 wherein said step of baking comprises baking at approximately 100° C. for approximately 30 minutes in a vacuum or inert environment.
Claim 84
Dependent Claim
105 words
A method as in claim 70 wherein said step of forming said patterned conductive layer comprising the steps of: forming a seed layer of conductive material on the surface of the device in a pattern resembling the desired pattern of the to-be-formed conductive layer; forming a layer of masking material on the surface of the device in a pattern to expose those portions of said seed layer where the inductor coil is to be formed; electroplating additional metal material to exposed portions of said seed layer; removing said masking layer; and removing those portions of said seed layer not covered by said additional conductive material.
Claim 85
Dependent Claim
24 words
A method as in claim 80 wherein said seed layer comprises TiW, Cu, Pd, Ti, Ni, Cr, Ag, Au, NiFe, or an alloy thereof.
Claim 86
Dependent Claim
38 words
A method as in claim 80 wherein said seed layer comprises a first layer of TiW formed to a thickness of approximately 200 Å and a second layer of copper formed to a thickness of approximately 1,000 Å.
Claim 87
Dependent Claim
20 words
A method as in claim 80 wherein said additional metal material comprises copper, silver, or gold, or an alloy thereof.
Claim 88
Dependent Claim
25 words
A method as in claim 80 wherein said additional metal material is formed to a thickness in the range of approximately 3 to 10 microns.
Claim 89
Dependent Claim
55 words
A method as in claim 80 wherein said step of forming said patterned conductive layer comprises the steps of: forming a layer of metallization; forming a mask in a desired pattern to protect those portions of said metallization layer which are to form said inductor coil; and removing exposed portions of said layer of metallization.
Claim 90
Dependent Claim
23 words
A method as in claim 80 further comprises the step of forming a clamping layer above at least portions of said inductor coil.
Claim 91
Dependent Claim
41 words
A method as in claim 86 wherein said step of forming a clamping layer comprises the step of forming a layer of material selected from the group of materials selected from the group of materials consisting of oxide, nitride, and photoresist.
Claim 92
Dependent Claim
25 words
A method as in claim 86 wherein said step of forming a clamping layer is performed after said step of removing said third dielectric layer.
Claim 93
Dependent Claim
25 words
A method as in claim 86 wherein said step of forming a clamping layer is performed before said step of removing said third dielectric layer.
Claim 94
Dependent Claim
16 words
A method as in claim 85 which further comprises the step of forming a passivation layer.
Claim 95
Dependent Claim
16 words
A method as in claim 86 which further comprises the step of forming a passivation layer.
Claim 96
Dependent Claim
31 words
A method as in claim 85 wherein said step of forming a layer of metallization serving as inductor coils also forms portions of said layer of metallization serving as electrical interconnects.
Claim 97
Dependent Claim
20 words
A method as in claim 92 wherein at least a portion of said electrical interconnects are formed on support studs.
Claim 98
Dependent Claim
59 words
A method as in claim 37 wherein said step of forming said second conductive layer comprises the step of: forming a layer of core material of a desired permeability, in a desired pattern; forming a first layer of insulating material above said core material layer; forming a second conductive layer in a pattern defining one or more inductor coils.
Claim 99
Dependent Claim
39 words
A method as in claim 94 which further comprises the steps of: forming a second insulation layer above said second conductive layer; and forming a second layer of core material of a desired permeability above said second insulating layer.
Claim 100
Dependent Claim
24 words
A method as in claim 70 wherein said third layer of dielectric comprises material which can be selectively etched with respect to said studs.
Claim 101
Dependent Claim
13 words
A method as in claim 37 wherein said substrate comprises a ferromagnetic material.
Claim 102
Dependent Claim
28 words
A method as in claim 37 which further comprises the steps of forming one or more layers of ferromagnetic core material in the vicinity of said inductor coil.
Claim 103
Dependent Claim
30 words
A method as in claim 98 wherein said one or more layers of ferromagnetic core material comprise a layer of ferromagnetic material located below and insulated from said inductor coil.
Claim 104
Dependent Claim
30 words
A method as in claim 98 wherein said one or more layers of ferromagnetic core material comprise a layer of ferromagnetic material located above and insulated from said inductor coil.
Claim 105
Dependent Claim
19 words
A method as in claim 98 wherein said layer of ferromagnetic core material comprises Ni/Fe, sandust, iron, or ferrites.
Claim 106
Dependent Claim
31 words
A method as in claim 98 wherein said one or more layers of ferromagnetic core material comprise Ni/Fe, having Fe within the range of approximately 20 to 60 percent by weight.
Claim 107
Dependent Claim
26 words
A method as in claim 98 wherein said step of forming said one or more layers of ferromagnetic core material is performed by deposition or sputtering.
Claim 108
Dependent Claim
41 words
A method as in claim 95 wherein said step of forming said one or more layers of ferromagnetic core material comprises the steps of: forming a seed layer in a desired pattern; and electroplating said ferromagnetic material onto said seed layer.
Claim 109
Dependent Claim
14 words
A method as in claim 104 wherein said seed layer is formed of Ni/Fe.
Claim 110
Dependent Claim
19 words
A method as in claim 104 wherein said seed layer is formed to a thickness of approximately 1,000 Å.
Claim 111
Dependent Claim
28 words
A method as in claim 104 wherein each said layer of ferromagnetic core material is formed to a thickness within the range of approximately 1 to 5 microns.
References Cited (Backward Citations)
US5071509A
Cited
US5227012A
Cited
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