The present invention relates to an electronic component and a manufacturing method thereof and, more particularly, to an electronic component having a capacitor and a manufacturing method thereof.
JP 2007-142109A and JP 2008-34626A disclose an electronic component having a capacitor and an inductor on a substrate. The capacitor described in JP 2007-142109A and JP 2008-34626A includes a lower electrode, a dielectric film that covers the lower electrode, and an upper electrode that faces the lower electrode through the dielectric film. In electronic components of such a type, a good conductor such as copper is used for the material of the upper and lower electrodes, and an inorganic insulating material such as silicon nitride is used for the dielectric film. The lower electrode is covered with an insulating layer made of an organic insulating material such as polyimide through the dielectric film. The organic insulating material such as polyimide has comparatively high adhesion to the silicon nitride, making interfacial peeling between the organic insulating material and the silicon nitride less likely to occur.
However, members constituting the electronic component have mutually different thermal expansion coefficients, causing internal stress due to a change in temperature. Concentration of such stress on the dielectric film made of silicon nitride may cause cracks in the dielectric film or interfacial peeling between the dielectric film and the insulating layer.
It is therefore an object of the present invention to provide an electronic component capable of relaxing internal stress due to a change in temperature and a manufacturing method for such an electronic component.
An electronic component according to the present invention includes: a substrate; a planarizing layer covering the surface of the substrate; a first conductive layer formed on the planarizing layer and having a lower electrode; a dielectric film made of a material different from that of the planarizing layer and covering the planarizing layer and first conductive layer; an upper electrode laminated on the lower electrode through the dielectric film; and a first insulating layer covering the first conductive layer, dielectric film, and upper electrode, wherein the outer periphery of the first insulating layer directly contacts the planarizing layer, not through the dielectric film.
According to the present invention, the outer periphery of the first insulating layer directly contacts the planarizing layer, so that it is possible to release internal stress due to a change in temperature at the contact point by selecting, as the material of the planarizing layer, a material lower in adhesion to the first insulating layer than the dielectric film to the first insulating layer.
The electronic component according to the present invention may further include a plurality of second conductive layers and a plurality of second insulating layers. The plurality of second conductive and insulating layers are alternately laminated on the first insulating layer. Some of the plurality of second insulating layers may have a cavity. This reduces the volume of the second insulating layers, allowing a reduction in stress to be applied to the second insulating layers. In this case, the plurality of second conductive layers may include a helical shaped conductive pattern constituting an inductor, and the cavity may be positioned within the inner diameter area of the helical shaped conductive pattern in a plan view. Thus, the inductor has an air-core structure, achieving a high self-resonant frequency and exhibiting a high Q-value in high frequency bands. Further, in this case, the planarizing layer may be exposed to the bottom of the cavity. This significantly reduces the volume of the first insulating layer and the plurality of second insulating layers, allowing a significant reduction in stress to be applied to the first insulating layer and the plurality of second insulating layers.
A manufacturing method for an electronic component according to the present invention includes the steps of: covering the surface of a substrate with a planarizing layer; forming, on the planarizing layer, a first conductive layer including a lower electrode; covering the planarizing layer and first conductive layer with a dielectric film made of a material different from that of the planarizing layer; laminating an upper electrode on the lower electrode through the dielectric film; and forming a first insulating layer covering the first conductive layer, dielectric film, and upper electrode after removing the outer periphery of the dielectric film.
According to the present invention, the outer periphery of the dielectric film is removed, so that the outer periphery of the first insulating layer directly contacts the planarizing layer, not through the dielectric film. Thus, it is possible to release internal stress due to a change in temperature at the contact point by selecting, as the material of the planarizing layer, a material lower in adhesion to the first insulating layer than the dielectric film to the first insulating layer.
The manufacturing method for an electronic component according to the present invention may further include a step of alternately laminating a plurality of second conductive layers and a plurality of second insulating layers on the first insulating layer and a step of forming a cavity in some of the plurality of second insulating layers. This reduces the volume of the plurality of second insulating layers, allowing a reduction in stress to be applied to the plurality of second insulating layers.
As described above, according to the present invention, there can be provided an electric component capable of relaxing internal stress due to a change in temperature and a manufacturing method of the same.
The above features and advantages of the present invention will be more apparent from the following description of certain preferred embodiments taken in conjunction with the accompanying drawings, in which:
Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.
The electronic component 1 according to the present embodiment is an LC filter and includes a substrate 2, conductive layers M1 to M4, and insulating layers I1 to I4 as illustrated in
The conductive layer M1 is a conductive layer positioned in the lowermost layer and includes conductive patterns 11 to 14. The conductive patterns 11 to 14 are each constituted of a thin seed layer S contacting the planarizing layer 3 and a plating layer P having a film thickness larger than that of the seed layer S. Similarly, the conductive patterns positioned in the conductive layers M2 to M4 are each formed of a laminated body of the seed layer S and plating layer P. A barrier layer (not illustrated) may be provided as a foundation of the seed layer S. The conductive pattern 13 has a loop shape in a plan view and constitutes a part of an inductor. The conductive pattern 14 constitutes a capacitor lower electrode and is covered at the upper and side surfaces thereof with a dielectric film (capacitive insulating film) 4 made of, e.g., silicon nitride. The dielectric film 4 is removed at the outer periphery of the electronic component 1, resulting in stress relaxation. The edge of the dielectric film 4 is positioned inside the end portion of the insulating layer I1 and outside the conductive patterns (conductive patterns 11 and 12 in the example of
The insulating layer I1 has comparatively high adhesion to the dielectric film 4 as a nitride film but has low adhesion to the planarizing layer 3 as an oxide film. Thus, interfacial peeling between the insulating layer I1 and the dielectric film 4 is less likely to occur in an element region having the dielectric film 4, whereas in the outer periphery having no dielectric film 4, interfacial peeling between the insulating layer I1 and the planarizing layer 3 is more likely to occur.
The conductive pattern 15 is formed on the upper surface of the conductive pattern 14 through the dielectric film 4. The conductive pattern 15 belongs to a conductive layer MM positioned between the conductive layers M1 and M2 and constitutes a capacitor upper electrode. This forms a capacitor having the lower and upper electrodes constituted by the conductive patterns 14 and 15, respectively. The conductive layers M1 and MM are covered with the insulating layer I1.
The conductive layer M2 is the second conductive layer, which is provided on the surface of the insulating layer I1 and includes conductive patterns 21 to 23. The conductive pattern 21 is connected to the conductive patterns 11 and 15 through openings formed in the insulating layer I1. The conductive pattern 23 has a loop shape in a plan view and constitutes a part of the inductor. The conductive layer M2 is covered with the insulating layer 12.
The conductive layer M3 is the third conductive layer, which is provided on the surface of the insulating layer and includes conductive patterns 31 to 33. The conductive pattern 31 is connected to the conductive pattern 21 through an opening formed in the insulating layer 12. The conductive pattern 32 is connected to the conductive pattern 22 through an opening formed in the insulating layer 12. The conductive pattern 33 has a loop shape in a plan view and constitutes a part of the inductor. The conductive layer M3 is covered with the insulating layer 13.
The conductive layer M4 is the fourth conductive layer, which is provided on the surface of the insulating layer 13 and includes conductive patterns 41 to 43. The conductive pattern 41 is connected to the conductive pattern 31 through an opening formed in the insulating layer 13. The conductive pattern 42 is connected to the conductive pattern 32 through an opening formed in the insulating layer 13. The conductive pattern 43 has a loop shape in a plan view and constitutes a part of the inductor. The conductive layer M4 is covered with the insulating layer I4.
Terminal electrodes E1 and E2 are provided on the upper surface of the insulating layer I4. The terminal electrodes E1 and E2 are connected respectively to the conductive patterns 41 and 42 through openings formed in the insulating layer I4.
As illustrated in
As illustrated in
Further, in the present embodiment, the outer periphery of the dielectric film 4 is removed, allowing the outer periphery of the insulating layer I1 to directly contact the planarizing layer 3, not through the dielectric film 4. As described above, the insulating layer I1 has a low adhesion to the planarizing layer 3, so that interfacial peeling easily occurs between the insulating layer I1 and the planarizing layer 3 in the outer periphery having no dielectric film 4. Thus, even when internal stress occurs due to a change in temperature, the interfacial peeling occurs between the insulating layer and the planarizing layer 3, releasing the internal stress.
The above effect is more prominent when the conductive layers M1 to M4 and insulating layers I1 to I4 are designed to be thick, or when the numbers of the conductive layers and insulating layers are larger. This is because an increase in the volume of constituent materials increases temperature-dependent dimensional change or internal stress to easily cause peeling in the capacitor, inductor, lead-out wires, and the like. That is, application of a thermal shock or humidity resistance load makes internal stress concentrate on the end portion of the insulating layer, which may generate peeling or crack to be directed inward toward the dielectric film 4. When the peeling or crack occurs in the dielectric film 4, the withstand voltage of the capacitor decreases. On the other hand, in the present embodiment, internal stress is released by the interfacial peeling between the insulating layer I1 and the planarizing layer 3, allowing prevention of peeling or crack of the dielectric film 4. The capacitor also undergoes stress from above; however, in the present embodiment, the presence of the cavity 52 relaxes this stress.
The following describes a manufacturing method for the electronic component 1 according to the present embodiment.
As illustrated in
Then, as illustrated in
Then, as illustrated in
Then, as illustrated in
Then, as illustrated in
Then, as illustrated in
Thereafter, the same processes are repeated to form the insulating layer 12, conductive layer M3, insulating layer 13, conductive layer M4, and insulating layer I4 in this order as illustrated in
Then, the insulating layer I4 is patterned to form openings 81, 82, and 86 to 89. As a result, the conductive patterns 41 and 42 are exposed respectively through the openings 81 and 82, and the sacrificial patterns 46 to 49 are exposed respectively through the openings 86 to 89. Subsequently, the terminal electrodes E1 and E2 are formed as illustrated in
Then, chemical etching is performed with the terminal electrodes E1 and E2 covered with a not-shown mask to thereby remove the sacrificial patterns 17 to 19, 27 to 29, 37 to 39, and 46 to 49. As a result, the cavity 51 is formed in the area of the sacrificial patterns 17, 27, 37, and 47 having been removed, and the cavity 52 is formed in the area of the sacrificial pattern 46 having been removed.
Then, the substrate 2 is cut along the area of the sacrificial patterns 18, 28, 38, and 48 having been removed, and the area of the sacrificial patterns 19, 29, 39, and having been removed to individualize the electronic components 1. As a result, the electronic component 1 according to the present embodiment is completed.
As described above, in the manufacturing method for the electronic component 1 according to the present embodiment, the sacrificial patterns 18, 19, 28, 29, 38, 39, 48, and 49 positioned on the dicing line are removed, so that even when the insulating layers I1 to I4 are large in thickness, a load to be applied to a dicing blade is significantly reduced, allowing the electronic components 1 to be easily individualized. Further, the dielectric film 4 on the dicing line is removed ahead of time, so that the dielectric film 4 is not subjected to dicing damage. Furthermore, the sacrificial patterns 17, 27, 37, 46, 47 are removed to form the cavities 51 and 52, thus reducing the volume of the insulating layers I1 to I4.
The electronic component 1A illustrated in
The electronic component 1B illustrated in
The electronic component 1C illustrated in
The electronic component 1D illustrated in
The electronic component 1E illustrated in
The electronic component 1F illustrated in
The electronic component 1G illustrated in
The electronic component 1H illustrated in
The electronic component 1I illustrated in
It is apparent that the present invention is not limited to the above embodiments, but may be modified and changed without departing from the scope and spirit of the invention.
For example, although the present invention is applied to an LC filter in the above embodiment, the electronic component as the subject matter of the present invention is by no means limited in application to the LC filter, and may be applied to electronic components of other types, such as those combined with an LCR element.
Further, the planarizing layer 3, dielectric film 4, and insulating layer I1 may be made of any materials as long as the adhesion between the planarizing layer 3 and the insulating layer I1 is lower than the adhesion between the dielectric film 4 and the insulating layer I1.
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