The present invention relates to a method for controlling a movable inductor and the device thereof, and more particularly to a method for controlling a movable inductor by using magnetism and the device thereof.
The on-chip inductor is an important element in the radio frequency integrated circuit (RFIC). However in the tradition, the parasitic capacitor and loss will arise between inductors which are parallel to the silicon substrate. Besides, when the inductor is powered on, a magnetic field is generated whose direction is perpendicular to the silicon substrate. This reduces the effect of storing energy and causes a low quality factor (Q) as well as a low self-resonant frequency (fres), which makes the on-chip inductor unfavorable to the industrial application.
The sensitivity of an ideal inductor will not change due to the magnitude of the current passing through the coil. However in practice, the resistor inside the inductor will consume the energy so that the quality thereof is affected. The higher the Q value is, the better the performance of the inductor is. Moreover, fres represents the upper limit of the operating frequency for an inductor. The performance of the inductor is normal only when the operating frequency is lower than fres. The influence of the parasitic capacitor on the inductor will be gradually increased when the operating frequency gradually approaches fres.
For improving the above-mentioned drawbacks, the inductor is separated from the substrate to enhance the Q value and fres, which has been achieved in the process of the micro-electro-mechanical system (MEMS). In IEEE MTT-S Digest, Phoenix, May, 2001, pp. 329-332, G W. Dahlmann et al. propose a method of using the surface tension resulting from the welding material which is heated and melted to elevate the structure. The elevated structure can be fixed when the welding material is solidified, thereby achieving the effect of self-assembling. However, such method cannot precisely control the elevating angle, and the Q value of the inductor as well as the corresponding fres also cannot be adjusted according to actual needs.
In order to overcome the drawbacks in the prior art, a method for controlling the movable inductor by using magnetism and the device thereof are provided. The particular design in the present invention not only solves the problems described above, but also is easy to be implemented. Thus, the present invention has the utility for the industry.
In accordance with one aspect of the present invention, a movable inductor using magnetism is provided. The movable inductor includes a substrate; a first structure layer disposed on the substrate, and having two protruding portions respectively disposed at two sides thereof; at least two fixing elements disposed on the substrate, and connected with the protruding portions; and a thermal bonding layer at least disposed on the fixing elements.
Preferably, the movable inductor further includes a metal layer disposed on the substrate and coplanar with the fixing elements, wherein a part of the thermal bonding layer is disposed on the metal layer.
Preferably, the metal layer includes one selected from a group consisting of Au, Ag, Cu, Ni, Au alloy, Ag alloy, Cu alloy and Ni alloy.
Preferably, the movable inductor further includes a metal layer disposed beneath the substrate.
Preferably, the metal layer includes one selected from a group consisting of Au, Ag, Cu, Ni, Au alloy, Ag alloy, Cu alloy and Ni alloy.
Preferably, the substrate has an inclined angle.
Preferably, the thermal bonding layer is one of a Sn layer and a Sn alloy layer.
Preferably, the first structure layer has a shape including one selected from a group consisting of a planar, a zigzag and a spiral shapes.
Preferably, the first structure layer includes a ferromagnetic material.
Preferably, the first structure layer is one of a Ni layer and a Ni alloy layer.
Preferably, the first structure layer further includes a second structure layer including a metal material being one selected from a group consisting of Au, Ag, Cu, Au alloy, Ag alloy and Cu alloy.
Preferably, the substrate is one selected from a group consisting of a Si substrate, a glass substrate, a Ge/Si substrate and a printed circuit board.
Preferably, the fixing elements are hinges including a metal material.
In accordance with another aspect of the present invention, a method for controlling a movable inductor by using magnetism is provided. The method includes steps of (a) providing a substrate; (b) forming a first structure layer on the substrate, wherein the first structure layer has two protruding portions respectively disposed at two sides thereof; (c) forming at least two fixing elements on the substrate, wherein the fixing elements are connected with the protruding portions; (d) forming a thermal bonding layer, which is at least disposed on the fixing elements; and (e) providing an alternating magnetic field to elevate the first structure layer via the protruding portions and the fixing elements by using a repulsion between like poles.
Preferably, the method further includes steps of (d1) placing the substrate on a metal layer; (e1) heating and melting the thermal bonding layer via the metal layer by using an electromagnetic induction; and (f) removing the alternating magnetic field for cooling the thermal bonding layer to fix a position of the first structure layer when the first structure layer is elevated to a specific angle.
Preferably, the method further includes steps of (d2) inclining the substrate; and (e2) performing at least one of changing a magnitude of the alternating magnetic field and adjusting a position of the alternating magnetic field.
Preferably, the metal layer includes one selected from a group consisting of Au, Ag, Cu, Ni, Au alloy, Ag alloy, Cu alloy and Ni alloy.
Preferably, the method further includes steps of (b1) forming a metal layer on the substrate, wherein the metal layer is coplanar with the fixing elements, and a part of the thermal bonding layer is disposed on the metal layer; (e1) heating and melting the thermal bonding layer via the metal layer by using an electromagnetic induction; and (f) removing the alternating magnetic field for cooling the thermal bonding layer to fix a position of the first structure layer when the first structure layer is elevated to a specific angle.
Preferably, the method further includes steps of (d2) inclining the substrate; and (e2) performing at least one of changing a magnitude of the alternating magnetic field and adjusting a position of the alternating magnetic field.
Preferably, the metal layer includes one selected from a group consisting of Au, Ag, Cu, Ni, Au alloy, Ag alloy, Cu alloy and Ni alloy.
Preferably, the thermal bonding layer is one of a Sn layer and a Sn alloy layer.
Preferably, the first structure layer includes a ferromagnetic material, is one of a Ni layer and a Ni alloy layer, and has a shape including one selected from a group consisting of a planar, a zigzag and a spiral shapes.
Preferably, the first structure layer further includes a second structure layer including a metal material being one selected from a group consisting of Au, Ag, Cu, Au alloy, Ag alloy and Cu alloy.
Preferably, the substrate is one selected from a group consisting of a Si substrate, a glass substrate, a Ge/Si substrate and a printed circuit board.
Preferably, the fixing elements are hinges including a metal material.
The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed descriptions and accompanying drawings, in which:
a) shows the operation of the movable inductor according to the first embodiment of the present invention;
b) is a lateral view of the movable inductor according to the first embodiment of the present invention;
a) shows the operation of the movable inductor according to the third embodiment of the present invention;
b) is a lateral view of the movable inductor according to the third embodiment of the present invention; and
The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for the purposes of illustration and description only; it is not intended to be exhaustive or to be limited to the precise form disclosed.
Please refer to
In this embodiment, the above-mentioned layers are formed on the Si substrate 10 by electroplating. However, this is only a preferred implementing way. The above-mentioned layers can also be formed on the Si substrate 10 by physical vapor deposition (PVD). Firstly, the first structure layer 110, the second structure layer 111, the protruding portions 12 and the metal layer 15 are sequentially formed on the Si substrate 10. Then, the fixing elements 13 are formed on the Si substrate 10. Finally, the thermal bonding layer 14 is formed on the metal layer 15 and the fixing elements 13. The manufacturing processes used in this embodiment are all prior arts, which will not be described here. In the above-mentioned steps, the first structure layer 110 and the second structure layer 11 are both lying on the Si substrate 10. The Si substrate 10 can be a Si substrate, a glass substrate, a Ge/Si substrate or a printed circuit board. The first structure layer 111 is made of a ferromagnetic material, e.g. Ni or Ni alloy. The fixing elements 13, the metal layer 15 and the second structure layer 111 are all made of a metal material, e.g. Au, Ag, Cu, Au alloy, Ag alloy or Cu alloy. The thermal bonding layer 14 is made of Sn or Sn alloy, for serving as a welding material to fix the first and the second structure layers 110, 111 after their positions are changed.
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When the movable inductor is within the alternating magnetic field 16, due to the electromagnetic induction principle, the metal layer 15 which has the maximum cutting area with the alternating magnetic field 16 will achieve a temperature sufficient to melt the thermal bonding layer 14. Please refer to
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Similarly, the first structure layer 210 is lying on the substrate 20 at present. Please refer to
The method of the second embodiment can also be used in this embodiment by elevating the metal layer 25 to an expected inclined angle or placing it on an inclined platform and then providing the alternating magnetic field 26, thereby completing the movable inductor at a specific angle.
Through the method of the present invention, the movable inductor has the effect of self-assembling. Besides, if the included angle between the first structure layer and the Si substrate is changed, the Q value of the inductor and the corresponding fres will be changed accordingly so that these two values can be arbitrarily adjusted. Hence, the angle can be changed according to actual needs. The following table shows the corresponding Q values and fres for three different angles.
Please refer to
The shapes of the first and the second structure layers 110, 111 can be planar, zigzag or spiral. The forms of the first and the second structure layers 110, 111 are not limited, which can be square, rectangular or round, etc. Furthermore, the number of zigzagging and whether the structures of the first and the second structure layers 110, 111 are single planes are not limited, which can be determined according to actual needs.
Based on the above, the present invention provides a method for controlling the movable inductor by using magnetism and the device thereof to freely control the elevating angle of the inductor and make it have the effect of self-assembling. Besides, the Q value of the inductor and the corresponding fres can be adjusted.
While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.
Number | Date | Country | Kind |
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098111084 | Apr 2009 | TW | national |