Patent Application
20120032297
This Application claims priority of Taiwan Patent Application No. 099126041, filed on Aug. 4, 2010, the entirety of which is incorporated by reference herein.
1. Field of the Invention
The present invention relates to an electronic device, and in particular relates to an electronic device with an opening.
2. Description of the Related Art
Many digital and analog elements and circuits have been successfully applied to semiconductor integrated circuits. Such elements may include passive components, such as resistors, capacitors, or inductors. Typically, a semiconductor integrated circuit includes a silicon substrate. One or more dielectric layers are formed on the substrate, and one or more metal layers are formed in the dielectric layers or thereon. The metal layers may be employed to form on-chip elements, such as on-chip inductors, by current semiconductor technologies.
Conventionally, an on-chip inductor is formed on an insulating layer on a substrate, wherein the inductor is electrically connected to an external circuit by the conductive plugs, the conductive layers and the signal output/input conductive traces. A principle advantage of the planar spiral inductor device is an increased level of circuit integration due to the reduced number of off-chip circuit elements and the complex interconnections required thereby.
In spiral inductor devices, there are three factors to estimate the quality factor (Q value) of the inductor devices, including skin effect, substrate eddy current and coil eddy current.
To reduce the skin effect loss, spiral conductive traces are widened or thickened. To improve the substrate eddy current loss, use of a grounding metal shielding layer, interposed between the spiral conductive trace and the semiconductor substrate, has been proposed. However, there is currently no way to improve the coil eddy current loss.
Since the performance of the inductor devices is based on the Q value, there is a need to develop an inductor device so that the coil eddy current loss can be improved.
The invention provides an electronic device, comprising: a substrate; and a conductive trace pattern formed on the substrate, wherein the conductive trace pattern has an opening to expose the substrate.
The invention also provides a spiral inductor device, comprising: a substrate; and a spiral conductive trace pattern with at least one turn formed on the substrate, wherein the spiral conductive trace pattern has an opening to expose the substrate.
The invention also provides a method for fabricating an electronic device, comprising: providing a substrate; and forming a conductive trace pattern on the substrate, wherein the conductive trace pattern has an opening to expose the substrate.
The invention also provides a method for fabricating a spiral inductor device, comprising: providing a substrate; and forming a spiral conductive trace pattern on the substrate, wherein the spiral conductive pattern has an opening to expose the substrate.
A detailed description is given in the following embodiments with reference to the accompanying drawings.
For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.
Refer to
Referring to
The substrate 10 may include a silicon substrate or other well-known semiconductor substrates. The substrate 10 may include various elements, such as transistors, resistors, or other well-known semiconductor elements. Moreover, the substrate 10 may also include other conductive layers (e.g. copper, aluminum or alloy thereof) and insulating layers (e.g. silicon oxide, silicon nitride or low-k dielectric materials). Hereinafter, to simplify the diagram, only a flat substrate is depicted.
The conductive trace pattern 20 is a single conductive trace, or a number of parallel or parallel conductive traces. The material of the conductive trace pattern 20 may comprise copper, aluminum or alloy thereof. The conductive trace pattern 20 has a first end 20a and a second end 20b to input/output signals. According to actual application needs, the first end 20a and the second end 20b separately connect to other interconnect structures (not shown in figures).
The opening 30 is formed in the conductive trace pattern 20 and the conductive trace pattern is divided into a first part 21 and a second part 22, wherein a width of the first part 21 may be larger, equal to or smaller than a width of the second part 22. Referring to
The opening 30 is extended from the first end 20a to the second end 20b. The opening 30 is extended from the top surface of the conductive trace pattern 20 down to the depth D which is the same as that of the thickness d of the conductive trace pattern 20. Thus, the substrate 10 below the opening 30 is exposed. Referring to
Additionally, the opening 30 comprises a continuous structure or a discontinuous structure, wherein the opening 30 is divided into a plurality of sections to form the discontinuous structure. Referring to
Moreover, referring to
According to Ampere's Law, as current flows through the electronic device, magnetic field is produced by the current. And, as the magnetic field passes through the conductive trace, an unwanted eddy current is induced. Because the original current and the eddy current interact with each other, the performance of the electronic device is reduced. In order to solve the above problems, an opening is formed in the conductive trace pattern of the electronic device of the invention, so that the amplitude of the magnetic field is changed by adjusting the position of the opening. Thus, the current of the conductive trace pattern is uniformly distributed to improve the performance of the electronic device.
The electronic device of the invention may be an inductor or other passive electronic devices, such as a transmission line or an energy storage device. All electronic devices in which performance may be affected by the uneven current are within the scope of the invention. Note that according to the shape and length of the conductive trace pattern, the position of the opening may be adjusted by those skilled in the art to change the amplitude of the magnetic field of the conductive trace pattern.
Refer to
Referring to
The spiral conductive trace pattern 200 has at least one turn and comprises an inner end 200a and an outer end 200b. All of the spiral conductive trace pattern 200 may substantially be in the same plane or not in the same plane. According to actual application needs, the first end 200a and second end 200b, separately connect to other interconnect structures (not shown in figures). In this embodiment, the spiral conductive trace pattern 200 extends from the outer end 200b to the inner end 200a clockwise. In other embodiment, the spiral conductive trace pattern 200 may extend counterclockwise. In
The spiral conductive trace pattern 200 may comprise a circular, rectangular, hexagonal, octagonal or polygonal shape, and comprises a rectangular shape as shown in the preferred embodiment in
The opening 300 extends from the inner end 200a to the outer end 200b. The opening 300 is extended from the top surface of the conductive trace pattern 200 down to the depth which is the same as that of the thickness of the conductive trace pattern 200. Thus, the substrate 100 below the opening 300 is exposed.
Referring to
Moreover, the opening 300 is formed along the spiral conductive trace pattern 200, and a length of the opening 300 is smaller than a length of the spiral conductive trace pattern 200. Furthermore, the opening 300 comprises a continuous structure or a discontinuous structure, wherein the opening 300 is divided into a plurality of sections to form the discontinuous structure. Referring to
Referring to
In prior art, when the current flows through the adjacent coils of the inductor, the magnetic field is generated in the adjacent coils (according to Ampere's law). When the magnetic field passes through the adjacent coil, an eddy current surrounding the coil is produced. The uneven current distribution of the coils caused by the eddy current will degrade the quality factor (Q value) of the inductor. Thus, the invention provides a spiral inductor, in which the opening is formed in the spiral conductive trace pattern to divide the spiral conductive trace pattern into two parts. The magnetic fields which are generated by the two parts, cancelled each other out to avoid eddy current. Thus, the current of the spiral conductive trace pattern is uniformly distributed, and quality factor of the inductor (Q value) is improved.
For example, referring to
The width (W1a,1b) of the first part 210, 230 may be larger than, equal to or smaller than the width (W2a,2b) of the second part 220, 240. In one embodiment, referring to
The invention also provides a method for fabricating an electronic device. The method comprises the following steps. A substrate is firstly provided and the material of the substrate is described above, so repeated description is omitted. Then, a conductive trace pattern is formed on the substrate, wherein the conductive trace pattern has an opening to expose the substrate. The conductive trace pattern with the opening is formed by coating a photoresist on the substrate, applying a photolithography technique (known to those skilled in the art), forming a specific pattern on the substrate, applying a deposition process (such as chemical deposition method or sputter method) to form the conductive trace pattern, and then removing the photoresist.
The invention also provides a method for fabricating a spiral conductive trace inductor. A substrate is firstly provided and a spiral conductive trace pattern is formed on the substrate, wherein the spiral conductive trace pattern has at least one turn and an opening to expose the substrate. The method for forming the spiral conductive trace pattern with the opening is the same as that of the above embodiments, so, repeated description is omitted.
The invention provides an electronic device and a spiral inductor device, in which an opening is formed in the conductive trace pattern. When current flows through the electronic device or the spiral inductor device, the magnetic field of the conductive trace pattern or the spiral conductive trace pattern is changed by the design of the opening to avoid an eddy current. Therefore, the performance of the electronic device and the quality factor (Q value) of the spiral inductor device are improved.
In the comparative embodiment, the width Wm of the spiral conductive trace pattern is about 25 μm and the spiral conductive trace pattern has 2.5 turns. The pitch P between neighboring turns of the spiral conductive trace pattern is about 3 μm. Note that there is no opening in the spiral conductive trace pattern.
In the embodiment 1, the width Wm of the spiral conductive trace pattern was about 25 μm and the spiral conductive trace pattern had 2.5 turns. The pitch P between neighboring turns of the spiral conductive trace pattern was about 3 μm. The width S of the opening was about 6 μm, the width W1a,1b of the first part was about 6.5 μm and the width W2a,2b of the second part was about 12.5 μm.
According to a computer calculated data, the quality factor of the embodiment 1 was higher than the comparative embodiment by about 25%.
In the embodiment 2, the width Wm of the spiral conductive trace pattern was about 25 μm and the spiral conductive trace pattern had 3.5 turns. The pitch P between neighboring turns of the spiral conductive trace pattern was about 2 μm. The width S of the opening was about 6 μm, the width W1a,1b of the first part was about 6.5 μm and the width W2a,2b of the second part was about 12.5 μm.
While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
| Number | Date | Country | Kind |
|---|---|---|---|
| 99126041 | Aug 2010 | TW | national |
