1. Field of the Invention
The present invention relates to an electronic component with a capacitor section to be built into a printed wiring board, and to a printed wiring board with a built-in electronic component.
2. Discussion of the Background
In Japanese Laid-Open Patent Publication 2008-227177, a method for manufacturing an electronic component to be mounted between a semiconductor element and a board substrate is described. Such a method for manufacturing an electronic component is as follows: (1) a step for embedding a signal-via conductor in an inorganic substrate; (2) a step for forming a coupling capacitor on a main surface of the inorganic substrate so that the coupling capacitor is connected to the embedded signal-via conductor by covering it; (3) a step for forming a signal pad on the side of an active element to be electrically connected to the coupling capacitor; and (4) a step for forming a signal pad on the board side to be electrically connected to the board substrate. The contents of this publication are incorporated herein by reference in their entirety.
According to one aspect of the present invention, an electronic component includes a substrate having a surface and one or more trench portions opening on the surface, a capacitor portion having a lower electrode formed on the surface of the substrate and on the wall surface of the trench portion, a dielectric layer formed on the lower electrode, and an upper electrode formed on the dielectric layer, a resin filler filling the space inside the trench portion lined by the upper electrode, an insulation layer formed on the surface of the substrate, a conductive portion formed on the insulation layer and positioned to cover the trench portion, and a via conductor connecting the conductive portion and either the lower electrode or the upper electrode.
According to another aspect of the present invention, a method for manufacturing an electronic component includes forming one or more trench portions in a substrate such that the trench portion has the opening on a surface of the substrate, forming on the surface of the substrate and the wall portion of the trench portion a capacitor portion having a lower electrode, a dielectric layer and an upper electrode, filling a resin filler in the space inside the trench portion lined by the upper electrode, forming an insulation layer on the surface of the substrate, forming a conductive portion on the insulation layer such that the conductive portion covers the trench portion, and forming a via conductor in the insulation layer such that the conductive portion is connected to either the lower electrode or the upper electrode.
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
The embodiments will now be described with reference to the accompanying drawings, wherein like reference numerals designate corresponding or identical elements throughout the various drawings.
A capacitor component structuring an electronic component according to the first embodiment of the present invention is described with reference to
As shown in
As shown in
As shown in
In capacitor component 10 of the first embodiment, capacitor section 40, which is formed with lower electrode 42, dielectric layer 44 and upper electrode 46, is formed on the surface (first surface) of substrate 20 as well as on the wall surfaces of trenches 30. Thus, the actual area between opposing electrodes is enlarged and higher capacitance is achieved. In addition, since resin filler 52 is filled in trenches 30, stress generated on the side walls of trenches 30 is absorbed by resin filler 52. Therefore, cracks occurring on the side walls of trenches 30 are suppressed even when trenches are formed at a narrow pitch to increase capacitance.
In capacitor 10 of the first embodiment, since resin insulation layer 50 is arranged on substrate 20, stress generated in substrate 20 is mitigated by insulation layer 50 when the capacitor is accommodated in a printed wiring board.
In capacitor 10 of the first embodiment, land portions 58 of electrode pads (12P, 12M) cover multiple trenches 30 by means of resin insulation layer 50. Accordingly, when resin filler 52 in trenches 30 expands due to heat, such expansion is suppressed by land portions 58 positioned over the filler. As a result, if stress is exerted on via conductors (60U, 60D) caused by thermal expansion of insulation layer 50, for example, such stress is mitigated, and that line breakage or the like of via conductors is suppressed.
In the following, steps for manufacturing capacitor component 10 are described with reference to
(1) Si wafer 20 with an approximate thickness of 300 μm is prepared (
(2) TiN film with a thickness of 10 nm is formed on Si wafer 20 by sputtering
(
(3) Next, W film with a thickness of 100 nm is formed on the TiN film by sputtering (
(4) Hard mask 70 made of SiO2 is formed on the W film by plasma CVD using TEOS (tetraethoxysilane) (
(5) A positive resist is applied on hard mask 70, which is then exposed to light and developed (TMAH) to form resist layer 72 with a predetermined pattern (
(6) Opening portion (70a) is formed by RIE (reactive ion etching) in hard mask 70 where resist layer 72 is not formed (FIG. 5(C)), and W film is exposed. The resist layer on hard mask 70 is removed (
(7) The W film exposed through opening portion (70a) in hard mask 70 is removed by etching, and opening (W-a) is formed in W film (
(8) Resist 74 with opening (74a) is formed on the W layer (
(9) The TiN layer exposed through opening (74a) in resist 74 is removed by etching (
(10) Spacer 76 made of SiO2 and having opening (76a) is formed on the W film by plasma CVD using TEOS (tetraethoxysilane) (
(11) Trench 30 is formed in Si wafer 20 by Si etching (FIG. 7(C)); the entire structure of trench 30 is shown in
(12) On the upper surface of Si wafer 20 and in trench 30, 30 nm-thick TiN film is further formed by CVD on the TiN film and W film already formed on Si wafer 20. Lower electrode 42 made of TiN/W/TiN is completed. Next, 12 nm-thick ZrSiO film is formed on lower electrode 42 by an ALD (Atomic Layer Deposition) process, and then 1 nm-thick AlO film is formed by ALD. Accordingly, dielectric layer 44 made of ZrSiO/AlO is completed. Furthermore, 20 nm-thick TiN film is formed by CVD on dielectric layer 44, and 10 nm-thick Ti film is formed by CVD (
(13) On the TiN film and Ti film already formed by sputtering, a 100 nm-thick W layer is formed. Accordingly, upper electrode 46 made of TiN/Ti/W is formed and capacitor section 40 is completed (
(14) Resin filler 52 is filled in trench 30 (
(15) A resist solution is applied, exposed to light and developed (TMAH). Accordingly, resist 78 with opening (78a) is formed (
(16) The TiN/Ti/W film which forms upper electrode 46 and is positioned in opening (78a) in resist 78 is removed by wet etching using an H2O2+KOH solution to expose dielectric layer 44 (
(17) Insulation layer 50 is formed, having opening (50a) for forming electrode pad (12M) and opening (50b) for forming electrode pad (12P) (
(18) Dielectric layer 44 exposed through opening (50a) is removed by wet etching and by diluted HF treatment (
(19) By TiN/Ti/Cu sputtering, seed layer 54 is formed with TiN (15 nm)/Ti (30 nm)/Cu (60 nm) on the surface of insulation layer 50 and in openings (50a, 50b) (
(20) Plating resist 55 with a predetermined pattern is formed, and electricity passes through seed layer 54 to form electrolytic copper-plated film 56 in portions where plating resist 55 is not formed (
(21) By removing the plating resist using a chemical solution, and by etching to dissolve seed layer 54 under the plating resist, via conductors (60U, 60D) and land portions 58 (electrode pads) are formed (
A printed wiring board with built-in capacitor component 10 of the first embodiment is described with reference to
Circuit patterns 134 are formed on the upper and lower surfaces of core substrate 130. Interlayer resin insulation layers 132 containing circuit patterns 158 and via conductors 160 are laminated as upper layers of core substrate 130. For interlayer resin insulation layers, thermosetting resin or thermoplastic resin without core material, or a composite of thermosetting resin and thermoplastic resin may be used. Moreover, through-hole conductors 136 which connect circuit patterns on the upper and lower surfaces of core substrate 130 are formed.
As upper layers of interlayer resin insulation layers 132, interlayer resin insulation layers 150 are formed containing circuit patterns 158 and via conductors 160. Moreover, as upper layers of interlayer resin insulation layers 150, interlayer resin insulation layers 250 are formed containing circuit patterns 158 and via conductors 160. As upper layers of interlayer resin insulation layers 250, solder-resist layers 70 are formed, and solder bumps 176 are formed in openings 71 of upper solder-resist layer 70.
Since Si capacitor 10 containing a high-capacitance capacitor section is accommodated directly under mounted IC chip 300 in a printed wiring board according to the first embodiment, the distance is reduced between the IC chip and the capacitor section, and power supply to the IC chip is intensified. Therefore, even if an increase in power consumption occurs instantaneously in a high-frequency IC chip, the voltage supply does not fall off, thus allowing the IC chip to continue operating properly. In such a case, it is preferred to form through-hole conductors in the capacitor component. In doing so, voltage is supplied to the IC chip through such through-hole conductors, and the voltage-supply circuit becomes shorter.
Printed wiring board with built-in Si capacitor 10 according to the second embodiment is described with reference to
In the printed wiring board according to the second embodiment, since Si capacitor 10 containing a high-capacitance capacitor section is accommodated directly under mounted IC chip 300, the distance is reduced between the IC chip and the capacitor section, and power supply to the IC chip is intensified. Therefore, even if an increase in power consumption occurs instantaneously in a high-frequency IC chip, the voltage supply does not fall off, thus allowing the IC chip to continue operating properly.
In the present embodiment, an electronic component is used as an interposer positioned between a printed wiring board and an IC chip. Its details are described with reference to
Interposer 10 as the electronic component in the third embodiment has through-hole conductors 62 to connect an upper surface (first surface) and a lower surface (second surface) of the substrate. Solder bumps 76 are formed on the lower-surface side. The first-surface side and the second-surface side of Si capacitor 10 are connected by the shortest possible route by using through-hole conductors 62.
Interlayer resin insulation layers (150, 250, 350) and circuit patterns 358 are alternately arranged on the upper surface of interposer 10. Interlayer circuit patterns are connected by via conductors 360. Solder bumps (76U) are positioned on uppermost circuit patterns 358. By means of solder bumps (76U), CPU chip 310 is mounted on the left of the drawing, and memory unit 320 is mounted on the right of the drawing. Memory unit 320 is formed with memory chips (322, 324, 326).
In the third embodiment, since IC chip 310 is mounted directly on interposer 10 containing high-capacitance capacitor section 40, the distance is reduced between IC chip 310 and capacitor section 40, and the power supply to the IC chip is intensified. Accordingly, even if an increase in power consumption occurs instantaneously in a high-frequency IC chip, the voltage supply does not fall off, thus allowing the IC chip to continue operating properly.
An electronic component according to an embodiment of the present invention has the following: a substrate with a first surface and having a trench portion (a recessed portion) which opens on the first surface; a capacitor section containing a lower electrode formed on the first surface of the substrate and on the wall surface of the trench portion, a dielectric layer formed on the lower electrode, and an upper electrode formed on the dielectric layer; resin filler filled in the space which is inside the trench portion and is lined by the upper electrode; an insulation layer formed on the first surface of the substrate; a conductive portion formed on the insulation layer; and a via conductor connecting either the lower electrode or the upper electrode and the conductive portion. In such an electronic component, the conductive portion is arranged to cover the trench portion.
In the electronic component above, since a capacitor section made up of a lower electrode, a dielectric layer and an upper electrode is formed on the wall surfaces of trench portions in the substrate, the actual area between the opposing electrodes is enlarged and higher capacitance is achieved. In addition, since resin filler is filled inside the trench portions, stress generated on the side walls of the trench portions, for example, is absorbed by the flexible resin filler. Thus, even if capacitance is enlarged by forming trench portions (recessed portions) at a narrow pitch, cracks do not occur on the side walls of the trench portions.
Furthermore, by arranging a conductive portion to cover resin filler in the trench portions, thermal expansion of the resin filler is suppressed, and stress exerted on a via conductor, for example, is mitigated, and line breakage or the like of the via conductor is suppressed.
In a printed wiring board according to another embodiment of the present invention, since an electronic component having a high-capacitance capacitor section is accommodated in a position directly under a mounted IC chip, the distance is reduced between the IC chip and the capacitor section, and the power supply to the IC chip is intensified. Therefore, even if an increase in power consumption occurs instantaneously in a high-frequency IC chip, the voltage supply does not fall off, thus allowing the IC chip to continue operating properly.
In a printed wiring board according to another embodiment of the present invention, since an IC chip is mounted directly on an electronic component having a high-capacitance capacitor section, the distance is reduced between the IC chip and the capacitor section, and the power supply to the IC chip is intensified. Therefore, even if an increase in power consumption occurs instantaneously in a high-frequency IC chip, the voltage supply does not fall off, thus allowing the IC chip to continue operating properly.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
The present application claims the benefits of priority to U.S. Application No. 61/319,035, filed Mar. 30, 2010. The contents of that application are incorporated herein by reference in their entirety.
Number | Date | Country | |
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61319035 | Mar 2010 | US |