KR20220064062A - Phase shifter - Google Patents

Abstract

The present invention relates to a phase shifter with electromagnetic interference (EMC) mitigation. According to an embodiment of the present invention, the phase shifter includes: a multilayer substrate in which a plurality of substrates are vertically stacked; a first helical pattern formed through a plurality of first patterns, a plurality of second patterns, and a plurality of first via holes in the multilayer substrate; and a second helical pattern formed through a plurality of third patterns, a plurality of fourth patterns, and a plurality of second via holes in the multilayer substrate, wherein the second helical pattern may be disposed inside the second helical pattern.

Description

Phase Shifter {PHASE SHIFTER}

The present invention relates to a phase converter having an electromagnetic interference (EMC) reduction function.

Recently, in accordance with the trend of larger and slimmer display devices, the display device is often mounted on a wall, and for convenient wireless connection with an external device that provides source content, such as a mobile device, Wi-Fi or Bluetooth ( There is a trend to embed a wireless communication module such as BT) in a display device.

However, when the large display device is mounted on a wall, it is difficult for radio waves to propagate between the wall and the display panel in the front direction of the display mainly due to the location of the wireless communication module mounted on the rear side of the display panel. Therefore, it is difficult to show excellent communication quality even when the wireless communication module of the display device and the external device to be wirelessly connected are relatively close. Accordingly, a method of correcting the propagation direction (ie, radiation pattern) of a radio signal by mounting a phase shifter on the antenna of the wireless communication module is being considered.

However, the conventional phase converter mainly employs an active method, so it has a large size, and has no function to reduce electromagnetic interference (EMC), so there is a problem in that a device for reducing EMC must be separately applied. In addition, when the antenna is first designed, it is difficult to correct the phase of the antenna feeding unit, so that it is difficult to correct the radiation pattern with only a single phase converter.

The present invention has been devised to solve the problems of the prior art, and is to provide a phase converter capable of further miniaturization and capable of phase correction and radiation pattern steering according to frequency.

Another object of the present invention is to provide a phase converter having an EMC reduction function.

The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

A phase converter according to an embodiment includes: a multilayer substrate on which a plurality of substrates are vertically stacked; a first helical pattern formed through a plurality of first patterns, a plurality of second patterns, and a plurality of first via holes in the multilayer substrate; and a second helical pattern formed through a plurality of third patterns, a plurality of fourth patterns, and a plurality of second via holes in the multilayer substrate, wherein the second helical pattern is disposed inside the first helical pattern. can

For example, each of the plurality of first patterns is disposed on a first substrate of the plurality of substrates, is spaced apart from each other and extends in parallel in a first direction, and each of the plurality of second patterns is a second pattern of the plurality of substrates. It is disposed on the substrate, and may be spaced apart from each other and extend side by side in the second direction.

For example, each of the plurality of first end pairs overlapping each other in the vertical direction among the ends of the plurality of first patterns and the ends of the plurality of second patterns forms different first via holes among the plurality of first via holes. can be electrically connected through.

For example, the plurality of substrates may include at least one third substrate disposed between the first substrate and the second substrate, and each of the plurality of first via holes may include the first substrate and the second substrate in a vertical direction. At least one third substrate and the second substrate may be penetrated.

For example, the at least one third substrate may include the plurality of third patterns and the plurality of fourth patterns spaced apart from the plurality of third patterns in a vertical direction.

For example, each of the plurality of second end pairs overlapping each other in the vertical direction among the ends of the plurality of third patterns and the ends of the plurality of fourth patterns forms a different second via hole among the plurality of second via holes. can be electrically connected through.

For example, each of the plurality of second via holes may pass through the at least one third substrate in a vertical direction.

For example, at least one of the plurality of third patterns may have a different extension direction from the other third patterns.

For example, the plurality of substrates may further include an uppermost substrate disposed on the first substrate and a lowermost substrate disposed under the second substrate.

For example, at least one of an upper surface of the uppermost substrate and a lower surface of the lowermost substrate may include a first electrode disposed on one side and a second electrode disposed on the other side opposite to the one side. converter.

For example, the second substrate may include a fifth pattern electrically connecting one end of the first helical pattern and the first electrode, and a fifth pattern electrically connecting the other end of the first helical pattern and the second electrode A sixth pattern may be further included.

A phase converter according to an embodiment includes: a plurality of substrates stacked in a vertical direction; a plurality of first patterns disposed in a first interlayer portion of a plurality of interlayer portions formed between two substrates facing each other in a vertical direction among the plurality of substrates and extending in parallel in a first direction while being spaced apart from each other; a plurality of second patterns disposed in a second interlayer among the plurality of interlayers, the plurality of second patterns being spaced apart from each other and extending side by side in a second direction; Between the first interlayer portion and the second interlayer portion, vertically connecting a plurality of first end pairs overlapping each other in a vertical direction among ends of the plurality of first patterns and ends of the plurality of second patterns a plurality of first via holes; a plurality of third patterns disposed in a third interlayer portion between the first interlayer portion and the second interlayer portion and extending apart from each other; a plurality of fourth patterns disposed between the first interlayer portion and the second interlayer portion, the third interlayer portion and the fourth interlayer portion spaced apart from each other in the vertical direction, and extending apart from each other; and vertically connecting a plurality of second end pairs overlapping each other in the vertical direction among the ends of the plurality of third patterns and the ends of the plurality of fourth patterns between the third interlayer and the fourth interlayer, respectively. and a plurality of second via holes.

For example, the plurality of first patterns, the plurality of second patterns, and the plurality of first via holes may form a first helical pattern, and the plurality of third patterns, the plurality of fourth patterns, and the plurality of first via holes may be formed. The second via hole may form a second helical pattern.

For example, the second helical pattern may be disposed inside the first helical pattern.

The effect of the phase converter according to the present invention will be described as follows.

First, it is possible to miniaturize the chip-type shape of the substrate stacking method, and it is possible to adjust the amount of phase change and impedance matching according to the number of stacked substrates.

Second, since the second helical pattern is disposed inside the first helical pattern, a high-frequency band stop function is implemented with a multi-resonant structure, which is advantageous in reducing electromagnetic interference.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned may be clearly understood by those of ordinary skill in the art to which the present invention belongs from the following description. will be.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are provided to help understanding of the present invention, and provide embodiments of the present invention together with detailed description. However, the technical features of the present invention are not limited to specific drawings, and features disclosed in each drawing may be combined with each other to form a new embodiment.
1 is a perspective view showing an example of a phase converter structure according to an embodiment.
2 is a perspective perspective view illustrating an example of a phase converter structure according to an embodiment.
3 is a perspective plan view illustrating an example of a phase converter structure according to an embodiment.
4 is a perspective side view illustrating an example of a phase converter structure according to an embodiment.
5 is a perspective perspective view illustrating an example of a structure of a phase converter according to another embodiment.
6A illustrates an example of an electric field distribution form of a phase shifting unit according to an embodiment, and FIG. 6B illustrates an example of an electric field distribution form of a resonator unit according to an exemplary embodiment.

Hereinafter, an apparatus and various methods to which embodiments of the present invention are applied will be described in more detail with reference to the drawings. The suffixes "module" and "part" for components used in the following description are given or mixed in consideration of only the ease of writing the specification, and do not have distinct meanings or roles by themselves.

In the description of the embodiment, in the case of being described as being formed in "above (above) or below (below)", "before (front) or after (rear)" of each component, "above (above) or below" "(below)" and "before (front) or after (behind)" include both components formed by direct contact with each other or one or more other components disposed between the two components.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the component from other components, and the essence, order, or order of the component is not limited by the term. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but another component is between each component. It should be understood that elements may be “connected,” “coupled,” or “connected.”

In addition, terms such as "comprises", "comprises" or "have" described above mean that the corresponding component may be embedded, unless otherwise specified, excluding other components. Rather, it should be construed as being able to further include other components. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs, unless otherwise defined. Terms commonly used, such as those defined in the dictionary, should be interpreted as being consistent with the meaning of the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present invention.

Hereinafter, a phase converter according to embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, a phase converter according to an embodiment will be described with reference to FIGS. 1 to 4 together.

1 is a perspective view illustrating an example of a phase converter structure according to an embodiment, and FIG. 2 is a perspective perspective view illustrating an example of a phase converter structure according to an embodiment. 1 and 2 have the same configuration except for reference numerals. 3 is a perspective plan view illustrating an example of a phase converter structure according to an embodiment, and FIG. 4 is a perspective side view illustrating an example of a phase converter structure according to an embodiment.

First, referring to FIG. 1 , the phase shifter 100 according to the embodiment includes a first electrode E1 positioned on one side along the uniaxial direction, and a second electrode positioned on the other side opposite to one side along the uniaxial direction ( E2), a phase shifting unit 110 forming a first helical pattern inside, and a resonator 120 forming a second helical pattern inside the first helical pattern. Here, the helical pattern refers to patterns and via holes arranged in a predetermined order (eg, first pattern - first via hole - second pattern - first via hole - repeating) while forming one or more turns in one direction (eg, uniaxial direction). ) may mean a polygonal spiral pattern extending to.

Here, the phase shift unit 110 connects the plurality of first patterns P1 , the plurality of second patterns P2 , the fifth pattern P5 , the sixth pattern P6 , and the plurality of first via holes VH1 to each other. may include Also, the resonator 120 may include a third pattern P3 , a fourth pattern P4 , and a plurality of second via holes VH2 . Each of the first to sixth patterns P1 , P2 , P3 , P4 , P5 , and P6 includes a conductive material, for example, copper, and may be formed in the form of a printed circuit on a substrate, but is not limited thereto.

Referring to FIG. 2 , the first electrode E1 includes a first upper electrode E1_T disposed on one side of the top surface of the phase converter 100 , and a first lower electrode E1_B disposed on one side of the bottom surface of the phase converter 100 . and a first electrode connection part E1_C extending in a vertical direction (ie, a three-axis direction) and electrically connecting the first upper electrode E1_T and the first lower electrode E1_B.

Similarly, the second electrode E2 includes a second upper electrode E2_T disposed on the other side of the upper surface of the phase converter 100 , a second lower electrode E2_B disposed on the other side of the bottom surface of the phase converter 100 , and a vertical direction. , and may include a second electrode connection part E2_C electrically connecting the second upper electrode E2_T and the second lower electrode E2_B.

The plurality of first patterns P1 , the plurality of second patterns P2 , and the first via holes VH1 may integrally form a first helical pattern extending along the uniaxial direction. The fifth pattern P5 may electrically connect one end HT1 of the first helical pattern to the first electrode E1 , and the sixth pattern P6 may include the other end of the first helical pattern and the second electrode E2 . ) can be electrically connected. According to the embodiment, when at least one of the fifth pattern P5 and the sixth pattern P6 corresponds to a part of a plurality of turns formed by the first helical pattern, the corresponding pattern is also regarded as constituting the first helical pattern. can

Each of the plurality of first patterns P1 ( P1_1 , P1_2 , P1_3 , and P1_4 ) may be spaced apart from each other on a plane, disposed side by side, and extend in one direction. Each of the plurality of first patterns P1 ( P1_1 , P1_2 , P1_3 , and P1_4 ) may have a predetermined width (eg, 40 μm) and a thickness (eg, 0.5 oz), and circular pads may be formed at both ends.

Each of the plurality of second patterns P2 ( P2_1 , P2_2 , and P2_3 ) may be spaced apart from each other on a plane and disposed side by side, and may extend in another direction different from one direction in which the first pattern P1 extends. Each of the plurality of second patterns P2 ( P2_1 , P2_2 , and P2_3 ) may have a width and a thickness corresponding to the plurality of first patterns P1 , and circular pads may be formed at both ends.

Each of the plurality of first end pairs overlapping each other in the vertical direction among the ends of the plurality of first patterns P1 and the ends of the plurality of second patterns P2 is, respectively, a plurality of first via holes VH1 extending in the vertical direction. ) can be electrically connected through one of the other. For example, one end T1 of the 1-4 patterns P1_4 and one end T2 of the 2-3 th patterns P2_3 overlap each other in the vertical direction to form one end pair, and vertically It may be electrically connected through one extended first via hole VH1.

Next, referring to FIG. 3 , the plurality of third patterns P3 , the plurality of fourth patterns P4 , and the second via holes VH2 may integrally form a second helical pattern extending along the uniaxial direction. there is. Unlike the first helical pattern, the second helical pattern may be insulated from each other without being electrically connected to the first electrode E1 and the second electrode E2 .

Each of the plurality of third patterns P3 ( P3_1 , P3_2 , and P3_3 ) may be spaced apart from each other on a plane, and an extension direction of at least one (eg, P3_2 ) may be different from the rest (eg, P3_1 and P3_3 ). Each of the plurality of third patterns P3 ( P3_1 , P3_2 , and P3_3 ) may have a predetermined width (eg, 40 μm) and a thickness (eg, 0.5 oz), and circular pads may be formed at both ends.

Each of the plurality of fourth patterns P4 P4_1 and P4_2 may be spaced apart from each other on a plane. Each of the plurality of fourth patterns P4 P4_1 and P4_2 may have a width and thickness corresponding to the plurality of third patterns P3 , and circular pads may be formed at both ends thereof.

Similar to the case of the first helical pattern, each of the plurality of second end pairs overlapping each other in the vertical direction among the ends of the plurality of third patterns P3 and the ends of the plurality of fourth patterns P4 is in the vertical direction, respectively. may be electrically connected to each other through a different one of the plurality of second via holes VH2 extending to the .

The uniaxial width W1 of the phase shifter 100 according to an embodiment may correspond to twice the biaxial width W2, and the diameter D of the via holes VH1 and VH2 is equal to each pattern ( It may be the same as the line width of P1, P2, P3, P4), but is not necessarily limited thereto. For example, when the line width of each pattern (P1, P2, P3, P4) is 40 μm, the uniaxial width (W1) is 1 mm, the biaxial width (W2) is 0.5 mm, and the diameter of the via hole (D) may be 40um.

Referring to FIG. 4 , the phase shifter 100 according to an embodiment may be implemented in the form of a multilayer substrate in which a plurality of substrates are stacked in a vertical direction (ie, a three-axis direction).

For example, a plurality of first patterns P1 are disposed on an upper surface of the first substrate S1, and a plurality of second patterns (P1) are disposed on a bottom surface of the second substrate S2 vertically spaced apart from the first substrate S1. P1), a fifth pattern P5 and a sixth pattern P6 may be disposed.

In addition, a third substrate S3 may be disposed between the first substrate S1 and the second substrate S1 , and a plurality of third patterns P3 may be disposed on the top surface of the third substrate S3 and the bottom surface of the third substrate S3 . A plurality of fourth patterns P4 may be disposed. A plurality of second via holes VH2 connecting between the third pattern P3 and the fourth pattern P4 may be formed to vertically penetrate the third substrate S3 .

In addition, the plurality of first via holes VH1 may be formed to vertically penetrate the first substrate S1 , the third substrate S3 , and the second substrate S2 .

An uppermost substrate TS may be disposed on the first substrate S1 , and a first upper electrode E1_T and a second upper electrode E2_T may be disposed on an upper surface of the uppermost substrate TS. In addition, a lowermost substrate BS may be disposed under the second substrate S2 , and a first lower electrode E1_B and a second lower electrode E2_B may be disposed on a lower surface of the lowermost substrate BS.

Here, the thickness of each substrate in the vertical direction (ie, the three-axis direction) is 100 μm, and the total thickness of the phase converter 100 including the electrode may be about 0.53 mm, but this is exemplary and is not necessarily limited thereto.

Although the third substrate S3 is illustrated as having one layer in FIG. 4 , a plurality of third substrates may be disposed to adjust the amount of phase change and match the impedance.

For example, when two third substrates are used, the third pattern P3 is disposed on the upper surface of the third substrate disposed thereon, and the fourth pattern P4 is the bottom surface of the third substrate disposed thereunder. The plurality of second via holes VH2 penetrate the two third substrates to electrically connect the third pattern P3 and the fourth pattern P4.

As another example, when three or more third substrates are used, the third pattern P3 is disposed on the upper surface of the third substrate disposed on the uppermost portion, and the fourth pattern P4 is disposed on the bottom surface of the third substrate disposed on the lowermost portion. may be disposed, and only via holes may be disposed in the third substrate excluding the top and bottom portions.

Of course, when a plurality of third substrates are used, the plurality of first via holes VH1 also extend further in the vertical direction by the increasing number of third substrates.

Depending on the implementation, the substrate on which each of the patterns P1 , P2 , P3 , P4 , P5 , and P6 is disposed may be different from the above-described description. For example, although the first pattern P1 has been described as being disposed on the upper surface of the first substrate S1 , according to another aspect, the first pattern P1 may be disposed on the bottom surface of the uppermost substrate TS. However, regardless of the type of substrate on which each of the patterns P1, P2, P3, P4, P5, and P6 is disposed, the relative positions between the patterns are maintained, so that the positions of each pattern are adjacent to each other in the vertical direction among the plurality of substrates ( Alternatively, it may be defined as a concept of an interlayer positioned between two substrates (opposite).

For example, in FIG. 4 , the first interlayer portion IL1 between the uppermost substrate TS and the first substrate S1, the third interlayer portion IL3 between the first substrate S1 and the third substrate S3, A fourth interlayer portion IL4 may be defined between the third substrate S3 and the second substrate S2 , and a second interlayer portion IL2 may be defined between the second substrate S2 and the lowermost substrate BS. In this case, the first pattern P1 is in the first interlayer part IL1 , the second pattern P2 is in the second interlayer part IL2 , and the third pattern P3 is in the third interlayer part IL3 . , the fourth pattern P4 may be viewed as being disposed on the fourth interlayer portion IL4.

In the phase shifter 100 according to the embodiment shown in FIGS. 1 to 4 , the first helical pattern of the phase shifter 110 is illustrated as forming 4 turns, but this is illustrative and includes the first helical pattern and the second helical pattern. 2 The number of turns of the helical pattern can be varied. This will be described with reference to FIG. 5 .

5 is a perspective perspective view illustrating an example of a structure of a phase converter according to another embodiment. The illustration of the second helical pattern is omitted in FIG. 5 to facilitate understanding.

Referring to FIG. 5 , in the phase shifter 100 ′ according to another exemplary embodiment, the first helical pattern of the phase shift unit 110 ′ forms 9 turns.

Hereinafter, effects of the phase shifters 100 and 100' according to the embodiment will be described.

6A illustrates an example of an electric field distribution form of a phase shifting unit according to an embodiment, and FIG. 6B illustrates an example of an electric field distribution form of a resonator unit according to an exemplary embodiment.

The phase shifter according to the embodiment increases the amount of phase change through a change in the number of stacked substrates (ie, a change in the height of the first via hole), and it is also possible to change a specific frequency at which impedance matching occurs.

As shown in FIG. 6A , when the first electrode E1 is an input terminal and the second electrode E2 is an output terminal, it can be seen that the electric field of the phase converter 110 becomes weaker from the input terminal to the output terminal.

Also, referring to FIG. 6B , it can be seen that the electric field is very weak in the central part, unlike both ends close to the electrodes E1 and E2 in the resonance part 120 , that is, the second helical pattern. This means that the transmission zero point occurs at the natural resonant frequency at which the impedance of the second helical pattern becomes 0, and the second helical pattern is inside the first helical pattern, so that the high-frequency signal is output at the output terminal (that is, due to the inductance effect of the first helical pattern) This is because it cannot go to the electrode) and is trapped inside. Accordingly, a high-frequency noise reduction function may be implemented by the resonator 120 of the phase converter 100 according to the embodiment.

In addition, due to the combination of the first helical pattern and the second helical pattern, it is possible to control the phase change in detail by adjusting the mutual inductance of the first helical pattern and the mutual inductance of the second helical pattern. In addition, when the second helical pattern is short-circuited, the size can be reduced by up to 1/2, thereby making it possible to further reduce the size. When the second helical pattern is shorted, resonance may occur at a point 1/4λ at a specific frequency, and when the second helical pattern is open, resonance may occur at a point 1/2λ of the specific frequency.

In the above, the embodiment has been mainly described, but this is only an example and does not limit the present invention, and those of ordinary skill in the art to which the present invention pertains are not exemplified above in a range that does not depart from the essential characteristics of the present embodiment. It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiment can be implemented by modification. And differences related to such modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

100, 100': phase shifter 110, 110': phase shift unit
120: resonator E1, E2: electrode

Claims (14)

a multilayer substrate in which a plurality of substrates are vertically stacked;
a first helical pattern formed through a plurality of first patterns, a plurality of second patterns, and a plurality of first via holes in the multilayer substrate; and
a second helical pattern formed through a plurality of third patterns, a plurality of fourth patterns, and a plurality of second via holes in the multilayer substrate;
The second helical pattern is disposed inside the first helical pattern, a phase converter. According to claim 1,
Each of the plurality of first patterns,
It is disposed on a first substrate among the plurality of substrates, is spaced apart from each other and extends side by side in a first direction,
Each of the plurality of second patterns,
The phase converter is disposed on a second substrate among the plurality of substrates, and is spaced apart from each other and extends side by side in a second direction. 3. The method of claim 2,
Each of the plurality of first end pairs overlapping each other in the vertical direction among the ends of the plurality of first patterns and the ends of the plurality of second patterns is electrically connected to each other through different first via holes among the plurality of first via holes Being a phase shifter. 4. The method of claim 3,
The plurality of substrates includes at least one third substrate disposed between the first substrate and the second substrate,
Each of the plurality of first via holes penetrates through the first substrate, the at least one third substrate, and the second substrate in a vertical direction. 4. The method of claim 3,
The at least one third substrate includes the plurality of third patterns and the plurality of fourth patterns spaced apart from the plurality of third patterns in a vertical direction. 6. The method of claim 5,
Each of the plurality of second end pairs overlapping each other in the vertical direction among the ends of the plurality of third patterns and the ends of the plurality of fourth patterns is electrically connected to each other through different second via holes among the plurality of second via holes Being a phase shifter. 7. The method of claim 6,
Each of the plurality of second via holes,
penetrating the at least one third substrate in a vertical direction. 6. The method of claim 5,
At least one of the plurality of third patterns has an extension direction different from that of the other third patterns, a phase converter. 3. The method of claim 2,
The plurality of substrates,
an uppermost substrate disposed on the first substrate; and
The phase converter further comprising a lowermost substrate disposed under the second substrate. 10. The method of claim 9,
At least one of an upper surface of the uppermost substrate and a lower surface of the lowermost substrate,
A phase converter comprising a first electrode disposed on one side and a second electrode disposed on the other side opposite to the one side. 11. The method of claim 10,
The second substrate may include a fifth pattern electrically connecting one end of the first helical pattern and the first electrode and a sixth pattern electrically connecting the other end of the first helical pattern and the second electrode. Further comprising, a phase converter. a plurality of substrates stacked in a vertical direction;
a plurality of first patterns disposed in a first interlayer portion of a plurality of interlayer portions formed between two substrates facing each other in a vertical direction among the plurality of substrates, and extending in parallel in a first direction while being spaced apart from each other;
a plurality of second patterns disposed in a second interlayer among the plurality of interlayers, the plurality of second patterns being spaced apart from each other and extending side by side in a second direction;
Between the first interlayer portion and the second interlayer portion, a plurality of first end pairs overlapping each other in the vertical direction among the ends of the plurality of first patterns and the ends of the plurality of second patterns are connected in a vertical direction, respectively a plurality of first via holes;
a plurality of third patterns disposed in a third interlayer portion between the first interlayer portion and the second interlayer portion and extending apart from each other;
a plurality of fourth patterns disposed between the first interlayer portion and the second interlayer portion, the third interlayer portion and the fourth interlayer portion spaced apart in the vertical direction, and extending apart from each other; and
Between the third interlayer portion and the fourth interlayer portion, a plurality of second end pairs overlapping each other in the vertical direction among the ends of the plurality of third patterns and the ends of the plurality of fourth patterns are connected in a vertical direction, respectively A phase converter comprising a plurality of second via holes. 13. The method of claim 12,
The plurality of first patterns, the plurality of second patterns, and the plurality of first via holes form a first helical pattern,
The plurality of third patterns, the plurality of fourth patterns, and the plurality of second via holes form a second helical pattern. 14. The method of claim 13,
and the second helical pattern is disposed inside the first helical pattern.

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