The present invention relates to an LC component, and more particularly to a thin film LC component suitable for reduction of thickness and to a mounting structure of the thin film LC component.
There is known a thin film IDP (Integrated Passive Device) in which an inductor and a capacitor are integrally formed on a silicon substrate or an alumina substrate by a thin film process (see, e.g., Japanese Unexamined Patent Application Publication No. 6-53406 and Japanese Unexamined Patent Application Publication No. 2001-44778). Japanese Unexamined Patent Application Publication No. 6-53406 discloses a technique of, in a step of fabricating a thin film circuit, forming a dielectric film for a thin film LC capacitor and an interlayer insulating film for a thin film inductor at the same time.
Japanese Unexamined Patent Application Publication No. 2001-44778 discloses a technique of constituting a capacitor by successively forming a first electrode layer, a dielectric layer, and a second electrode layer on a substrate, and forming, on the capacitor, a planar inductor that is made up of magnetic films and a coil, thereby ensuring isolation between the capacitor and the inductor.
Because the IPD is a passive component formed by the thin film process, its thickness can be considerably reduced in comparison with thicknesses of passive components that are formed by a thick film process and a sheet multilayer process. However, when the inductor and the capacitor are flush with each other as in Japanese Unexamined Patent Application Publication No. 6-53406, a necessary substrate area is increased, and an increase in size of the thin film IPD is unavoidable. On the other hand, when the capacitor is formed on the substrate and the inductor is formed on the capacitor as in Japanese Unexamined Patent Application Publication No. 2001-44778, the necessary substrate area is reduced. However, when such an LC passive component is mounted to a printed wiring board or the like, a distance between a circuit on the printed wiring board and the capacitor is increased relatively, thus causing a parasitic inductance therebetween. Accordingly, electrical characteristics of the LC passive component change depending on a state of mounting to the printed wiring board or the like.
An object of the present invention is to provide a thin film LC component being thin and having a small area, in which a parasitic inductance of a thin film capacitor is suppressed, and to provide a mounting structure of the thin film LC component.
A thin film LC component, comprising:
a substrate that has first and second opposing surfaces;
a thin film capacitor located on the first surface;
a thin film inductor located on a region of the second surface, the region at least partially overlapping the thin film capacitor when viewed in plan;
interlayer connection conductors located in the substrate and connecting the thin film capacitor to the thin film inductor;
an insulating layer located over the first surface and covering the thin film capacitor; and
a plurality of terminal electrodes located on a surface of the insulating layer and being connected to both the thin film capacitor and the thin film inductor, the terminal electrodes being connected to a circuit on a mounting substrate.
With the features described above, an area of a region where the thin film capacitor and the thin film inductor are formed is reduced when viewed in plan. Furthermore, since the terminal electrodes are formed on the substrate not at the side where the thin film inductor is formed, but at the side where the thin film capacitor is formed, the thin film capacitor can be arranged at a shortest distance relative to a circuit formed on a printed wiring board (mounting substrate), and a parasitic inductance is reduced. Moreover, since the substrate is interposed between the thin film inductor and the thin film capacitor, namely since the thin film inductor is positioned away from the thin film capacitor, an eddy current is less apt to flow in electrode films of the thin film capacitor. Hence the thin film inductor having a higher Q-value is constituted.
Preferably, each of the thin film inductor and the thin film capacitor has a first end and a second end, the first end of the thin film capacitor and the second end of the thin film inductor are connected to each other, and the plurality of terminal electrodes are constituted by at least three terminal electrodes that are connected respectively to the first end of the thin film capacitor, a second end of the thin film capacitor, and a first end of the thin film inductor. With the features described above, it is just needed from an electrical point of view that the three terminal electrodes are disposed in a state exposed to the outside. Thus, an LC low pass filter or a smoothing circuit, for example, can be constituted just by connecting those terminal electrodes to the circuit on the substrate.
In an embodiment, the thin film inductor is constituted by a plurality of thin film inductors each having a first end and a second end, and the plurality of terminal electrodes include a terminal electrode that is connected to the first ends of the plurality of thin film inductors. With the features described above, low pass filters or smoothing circuits having different time constants can be selectively used in combination of plural inductors and a common capacity.
In an embodiment, the thin film capacitor includes a first electrode film parallel to the first surface, a second electrode film opposing to the first electrode film, and a dielectric thin film interposed between the first electrode film and the second electrode film, the dielectric thin film being a barium strontium titanate thin film. With the features described above, the thin film capacitor with a high capacitance in spite of having a small area can be constituted, and hence the thin film LC component having a small size can be constituted.
In an embodiment, a total thickness of the substrate, the thin film capacitor, the thin film inductor, and the insulating layer is not more than 100 When the total thickness has such a size, the thin film LC component can be disposed in a gap between a face plane of a semiconductor chip and a mounting substrate, the semiconductor chip being face-down mounted to the mounting substrate with bumps interposed therebetween.
In another embodiment a mounting structure is provided for a thin film LC component, the mounting structure being adapted to mount a semiconductor chip, a capacitor, and an inductor to a mounting substrate. The semiconductor chip is face-down mounted to the mounting substrate with bumps interposed therebetween. The capacitor and the inductor are constituted as a thin film LC component comprising a substrate that has a first surface and a second surface opposing to each other, a thin film capacitor that is formed on the first surface by a thin film process, a thin film inductor that is formed in a region of the second surface by a thin film process, the region at least partially overlapping the thin film capacitor when viewed in plan, interlayer connection conductors that are formed in the substrate and connect the thin film capacitor and the thin film inductor to each other, an insulating layer that is formed over the first surface and covers the thin film capacitor, and terminal electrodes that are formed on a surface of the insulating layer and are connected to the thin film capacitor and the thin film inductor. The thin film LC component is disposed in a gap between the mounting substrate and the semiconductor chip.
With the features described above, the thin film LC component being thin and having a small area, or the thin film LC component in which a parasitic inductance of the thin film capacitor is suppressed can be mounted to the mounting substrate together with the semiconductor chip at a high density.
The present invention makes it possible to provide a thin film LC component which is thin and which has a small area and the parasitic inductance is suppressed. The present invention further provides a small-sized electronic device including the thin film LC component.
Embodiments for carrying out the present invention will be described below in connection with several practical examples by referring to the drawings. In the drawings, the same members are denoted by the same reference signs. Although the embodiments are described in separated forms in consideration of easiness in explanation of principal matters and understanding, individual features of the different embodiments can be partially replaced or combined with each other. In the second and subsequent embodiments, description of common matters to those in the first embodiment is omitted, and only different points are described. In particular, similar advantageous effects obtained with similar features are not specifically described in each of the embodiments.
As best shown in
Through-silicon vias 61 and 62 connecting the thin film capacitor TFC and the thin film inductor TFL are formed in the substrate 10. A solder resist film (insulating layer) 31 covering the thin film capacitor TFC is formed on the first surface S1 of the substrate 10. Terminal electrodes 51, 52 and 53 connected to the thin film capacitor TFC and the thin film inductor TFL are formed on a surface of the solder resist film 31.
The thin film LC component 101 according to this embodiment acts as a low pass filter or a smoothing circuit with the port P3 held at a ground potential, the port P1 being an input port, and the port P2 being an output port.
This embodiment has the following advantageous effects.
An area of a region where the thin film capacitor TFC and the thin film inductor TFL are formed is reduced when viewed in plan. Furthermore, since the terminal electrodes 51, 52 and 53 are formed on the substrate 10 not at the side where the thin film inductor TFL is formed, but at the side where the thin film capacitor TFC is formed, the thin film capacitor TFC can be arranged at a shortest distance relative to a circuit formed on a printed wiring board (mounting substrate), and a parasitic inductance is reduced. Therefore, a resonant frequency of LC serial resonance generated by the parasitic inductance and the thin film capacitor TFC can be made higher than a frequency band to be used, and low pass filter characteristics or smoothing characteristics can be obtained over a wide range.
Moreover, since the substrate 10 is interposed between the thin film inductor TFL and the thin film capacitor TFC, namely since the thin film inductor TFL is positioned away from the thin film capacitor TFC, an eddy current is less apt to flow in electrodes of the thin film capacitor TFC. Hence the thin film inductor TFL having a higher Q-value is constituted.
A detailed structure of the thin film LC component 101 illustrated in
Step (1) In
Step (2) As illustrated in
Step (3) As illustrated in
Step (4) As illustrated in
Step (5) As illustrated in
Step (6) As illustrated in
Step (7) As illustrated in
Step (8) As illustrated in
Step (9) As illustrated in
Step (10) Then, the thin film LC component 101 illustrated in
Although
A second embodiment represents a thin film LC component 102 that is formed by integrating a thin film capacitor TFC and a thin film inductor TFL with each other, which are fabricated separately.
In the thin film LC component 102 according to this embodiment, the thin film capacitor TFC is located on a first surface S1 of a substrate 10C, and the thin film inductor TFL is located on a second surface S2 of a substrate 10L.
A detailed structure of the thin film LC component 102 according to this embodiment, and a manufacturing method for the thin film LC component 102 will be described below with reference to
Step (1) In
Step (2) A solder resist film 32 covering the conductor pattern 70 is coated to be formed thereon. Thereafter, through-silicon vias (TSV's) 61 and 62 are formed in the substrate 10L. As a result, the thin film inductor TFL including the through-silicon vias 61 and 62 are constituted.
Step (3) As illustrated in
Then, the substrate 10L including the thin film inductor TFL formed thereon, illustrated in
Step (4) Then, as illustrated in
As described above in this embodiment, the thin film LC component may be constituted by forming the thin film capacitor and the thin film inductor on separate substrates, and then bonding both the substrates to each other.
A third embodiment represents an example of a mounting structure of a thin film LC component and an example of an electronic component including the thin film LC component.
An electronic component 201 of the Sip structure is achieved by sealing a space above the mounting substrate 80 with a sealing resin 82. The electronic component 201 is preferably also a package of BGA (Ball Grid Array) type using solder balls 81, and is surface-mounted to a circuit board 200.
It is to be noted that, without limitation, the thin film LC component 101 may be bonded to the semiconductor chip 90 instead of the mounting substrate 80.
A fourth embodiment represents an example in which the thin film LC component is applied to a microprocessor including a plurality of circuits operated with different power supply voltages.
A fifth embodiment represents an example of a thin film LC component including a plurality of thin film inductors.
With the structure illustrated in
With the structure illustrated in
While the first embodiment illustrates an example in which almost the entirety of the thin film inductor TFL is formed in the region overlapping the thin film capacitor TFC when viewing the substrate 10 in plan, part of the thin film inductor TFL may be formed in the region overlapping the thin film capacitor TFC. When at least part of the thin film inductor TFL is formed in the region overlapping the thin film capacitor TFC, the area of a region where the thin film capacitor TFC and the thin film inductor TFL are formed is reduced when viewed in plan.
While, in the example illustrated in
While the first embodiment represents the example in which a high-resistance Si substrate is used as the substrate, a glass substrate, an alumina ceramic substrate, or the like may also be used instead.
While, in the first embodiment, the thin film capacitor is first formed on the substrate and the thin film inductor is formed later thereon, the order of forming the thin film capacitor and the thin film inductor on the substrate may be reversed. Furthermore, between the step of forming the thin film capacitor and the step of forming the thin film inductor, the substrate may be polished to reduce its thickness.
In the first embodiment, the through-silicon vias (TSV's) are formed in the substrate (high-resistance Si substrate) 10. The through-silicon vias are each formed by boring a through-hole in the Si substrate, and filling Cu into the through-hole by plating. However, a through conduction path may be formed instead of the TSV by doping, namely by implanting an impurity into the Si substrate.
While the first embodiment represents the example of forming the solder resist films 31 and 32 that are organic interlayer insulating films, inorganic insulating films may be formed instead by a plasma CVD process, for example. Alternatively, the insulating film may be formed by bonding an insulating resin sheet.
While, in the above embodiments, a semiconductor substrate is used, by way of example, as the “substrate” in the present invention, a glass substrate or a ceramic substrate may also be used.
Finally, it is to be noted that the above description of the embodiments is not restrictive, but illustrative in all respects. The above embodiments can be modified and changed as appropriate by those skilled in the art. For instance, the individual structures described in the different embodiments can be partially replaced or combined with each other. The scope of the present invention is defined in not the above description of the embodiments, but in Claims. Moreover, the scope of the present invention is intended to include all modifications that are equivalent to Claims in terms of meaning and scope.
H1, H2, H3 . . . hole
H61, H62 . . . hole
L1, L2, L3, L4 . . . thin film inductor
P1, P2, P3 . . . port
P11, P12, P13, P14 . . . port
PSa, PSb, PSc, PSd . . . power supply circuit
S1 . . . first surface
S2 . . . second surface
TFC . . . thin film capacitor
TFL . . . thin film inductor
TSV . . . through-silicon via
10, 10C, 10L . . . substrate
21, 23, 25 . . . BST film
22, 24 . . . Pt electrode film
31, 32 . . . solder resist film (insulating layer)
41, 42, 43 . . . via electrode
51, 52, 53 . . . terminal electrode
61, 62 . . . through-silicon via
70 . . . conductor pattern
80 . . . mounting substrate
81, 91 . . . solder ball
82 . . . sealing resin
90 . . . semiconductor chip
98 . . . microprocessor chip
101, 102 . . . thin film LC component
101
a,
101
b,
101
c,
101
d . . . smoothing circuit
200 . . . circuit board
201 . . . electronic component
221, 222 . . . Pt electrode film
Number | Date | Country | Kind |
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2015-196392 | Oct 2015 | JP | national |
The present application is a continuation of International application No. PCT/JP2016/078552, filed Sep. 28, 2016, which claims priority to Japanese Patent Application No. 2015-196392, filed Oct. 2, 2015, the entire contents of each of which are incorporated herein by reference.
Number | Date | Country | |
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Parent | PCT/JP2016/078552 | Sep 2016 | US |
Child | 15928217 | US |