Laminated chip inductor

Abstract

The invention provides a laminated chip inductor, and relates to the field of electronic elements. The laminated chip inductor comprises at least one stacking unit, the stacking unit comprises a first printing layer and a second printing layer, a coil structure of the first printing layer comprises a first guide hole and a second guide hole, a coil structure of the second printing layer comprises a third guide hole and a fourth guide hole, and projections of adjacent upper and lower coil structures are overlapped to form an encircling structure. The first guide hole and the third guide hole are used for connecting the first printing layer and the second printing layer, the second guide hole and the fourth guide hole are used for connecting two adjacent stacking units, and at least one of two corners, far away from the guide holes, in the coil structure is an arc-shaped corner. The arc-shaped corners of the first printing layer and the second printing layer are located at the same corner position in the lamination direction. By arranging the arc-shaped corner, extra loss caused by charge accumulation at the corner when charges flow through the right-angle structure is avoided, the error between an actual L value and a theoretical L value is reduced, and meanwhile, the Q value is increased.

Description

Technical Field

[0001] The invention belongs to the field of electronic components, and in particular relates to a laminated chip inductor. Background Art

[0002] The multilayer chip inductor is made by alternately printing multiple layers of ferrite or ceramic slurry and conductive slurry to obtain a laminate containing multiple layers of internal electrodes, which is then co-sintered at low temperature to form an inductor coil with a closed magnetic circuit, and then coated with end electrodes.

[0003] Inductance (L value) and quality factor (Q value) are the most important parameters and quality indicators of multilayer chip inductors. In related technologies, the required L value is obtained by designing and adjusting the number of layers of the laminate and the screen structure of the printed internal electrodes. However, there is a certain error between the L value actually obtained and the theoretical design L value. The existence of the error leads to a decrease in the inductance accuracy of the multilayer chip inductor. In addition to changing the type of materials used, the Q value can also be improved by designing the internal electrodes. However, the process difficulty of achieving the required printing accuracy and stable printing repeatability also increases accordingly. Poor printing quality or poor reproducibility leads to a larger error between the theoretical L value and the theoretical design L value. Summary of the invention

[0004] The main purpose of the present invention is to provide a multilayer chip inductor that can reduce the error between the theoretical L value and the actual L value while simultaneously meeting the need to improve the Q value.

[0005] To achieve the above object, one aspect of the present invention provides a multilayer chip inductor, comprising:

[0006] At least one stacking unit, the stacking unit includes a first printing layer and a second printing layer, the first printing layer and the second printing layer both include a ceramic layer and a coil structure on the ceramic layer, the projections of the adjacent upper and lower coil structures overlap to form an enclosed structure, the coil structure of the first printing layer includes a first guide hole as a starting end and a second guide hole as a terminating end, and the coil structure of the second printing layer includes a third guide hole as a terminating end and a fourth guide hole as a starting end;

[0007] The first guide hole and the third guide hole are used to connect the first printing layer and the second printing layer, and the second guide hole and the fourth guide hole are used to connect two adjacent stacking units;

[0008] The coil structures each include four corners, and at least one of the two corners farther from the guide hole is an arc-shaped corner;

[0009] The length of the circumscribed side of the arc corner in the first direction of the coil structure is greater than 0 and is less than or equal to half of the length of the side of the coil structure in the first direction; the length of the circumscribed side of the arc corner in the second direction of the coil structure is greater than 0 and is less than or equal to half of the length of the side of the coil structure in the second direction; the angle value corresponding to the arc corner is greater than 0 and is less than or equal to 2 times the value of the inverse tangent function of the smaller value of the circumscribed side of the coil structure in the first direction and the circumscribed side of the coil structure in the second direction divided by the larger value of the circumscribed side of the coil structure in the first direction and the circumscribed side of the coil structure in the second direction; the radius of the circle where the arc corner is located is greater than 0.5 times the square root of the sum of the square of the circumscribed side of the coil structure in the second direction of the arc corner and the square of the circumscribed side of the coil structure in the first direction;

[0010] The arc-shaped corner of the first printing layer and the arc-shaped corner of the second printing layer are located at the same corner position in the stacking direction.

[0011] In some embodiments, the parameters of the arc corner include the circumscribed side length in the first direction, the circumscribed side length in the second direction, the angle value and the radius, and the parameters of the arc corner of the first printing layer are the same as the parameters of the arc corner of the second printing layer.

[0012] In some embodiments, the coil structure includes a first short side in the first direction, a short side in the second direction, a long side in the first direction, a long side in the second direction, and a second short side in the first direction;

[0013] The first guide hole of the first printing layer is located at one end of the first short side in the first direction, and the second guide hole of the first printing layer is located at one end of the second short side in the first direction; the coil structure of the first printing layer is formed by sequentially connecting the first guide hole, the first short side in the first direction, the short side in the second direction, the long side in the first direction, the long side in the second direction, the second short side in the first direction, and the second guide hole;

[0014] The third guide hole of the second printed layer is located at one end of the first short side in the first direction, and the fourth guide hole of the second printed layer is located at one end of the second short side in the first direction; the coil structure of the second printed layer is formed by sequentially connecting the fourth guide hole, the second short side in the first direction, the long side in the second direction, the long side in the first direction, the short side in the second direction, the first short side in the first direction and the third guide hole.

[0015] In some embodiments, there is at least one arc-shaped corner among the corner where the long side in the first direction is connected to the short side in the second direction and the corner where the long side in the first direction is connected to the long side in the second direction.

[0016] In some embodiments, when the corner connecting the long side in the first direction and the short side in the second direction is an arc-shaped corner, the circumscribed side length of the arc-shaped corner in the second direction is greater than 0 and less than or equal to 0.5 times the short side in the second direction; the radius of the circle in which the arc-shaped corner is located is less than or equal to half of the short side in the second direction.

[0017] In some embodiments, when the corner connecting the long side in the first direction and the long side in the second direction is an arc-shaped corner, the circumscribed side length in the second direction of the arc-shaped corner is greater than 0 and less than or equal to 0.426 times the long side in the second direction; the radius of the circle in which the arc-shaped corner is located is less than or equal to 0.426 times the long side in the second direction.

[0018] In some embodiments, the length of the circumscribed side of the arc-shaped corner in the first direction is greater than or equal to 0.1 times the long side in the first direction, and less than or equal to 0.4 times the long side in the first direction.

[0019] In some embodiments, when the corner connecting the long side in the first direction and the short side in the second direction is an arc-shaped corner, the second-direction circumscribed side length of the arc-shaped corner is greater than or equal to 0.065 times the short side in the second direction, and less than or equal to 0.26 times the short side in the second direction; the angle value corresponding to the arc-shaped corner is greater than or equal to 28 degrees and less than or equal to 90 degrees.

[0020] In some embodiments, when the corner connecting the long side in the first direction and the long side in the second direction is an arc-shaped corner, the circumscribed side length in the second direction of the arc-shaped corner is greater than or equal to 0.056 times the long side in the second direction, and less than or equal to 0.22 times the long side in the second direction; the angle value corresponding to the arc-shaped corner is greater than or equal to 28 degrees and less than or equal to 90 degrees.

[0021] In some embodiments, the coil structure of the first printing layer has two arc-shaped corners; the coil structure of the second printing layer has two arc-shaped corners.

[0022] In some embodiments, the angle values ​​of the two arc-shaped corners of the coil structure of the first printing layer are equal; the angle values ​​of the two arc-shaped corners of the coil structure of the second printing layer are equal.

[0023] In some embodiments, the first guide hole of the first printing layer and the third guide hole of the second printing layer are aligned in the stacking direction; the second guide hole of the first printing layer and the fourth guide hole of the second printing layer are aligned in the stacking direction.

[0024] In some embodiments, the guide hole on the coil structure is in the shape of a perfect circle or an ellipse tangent to the first short side in the first direction or the second short side in the first direction.

[0025] In some embodiments, two corner edges of the coil structure close to the guide hole are chamfered.

[0026] In some embodiments, the multilayer chip inductor further includes an introduction layer and a lead-out layer, a plurality of the stacked units are arranged between the introduction layer and the lead-out layer, the introduction layer and the lead-out layer both include a ceramic layer and a coil structure on the ceramic layer, the starting end of the coil structure on the introduction layer is connected to the second guide hole of the coil structure of the first printed layer, and the ending end of the coil structure on the lead-out layer is connected to the fourth guide hole of the coil structure of the second printed layer.

[0027] The above-mentioned technical scheme of the present invention has at least the following advantages or beneficial effects: the technical scheme avoids the accumulation of charges at the corners when the charges flow through the right-angle structure and causes additional losses by selectively designing the corners in the coil structure as arc-shaped corners, and fine-tuning the effective area and the effective length, so that the size of the multilayer chip inductor is moderate and the error value between the actual L value and the theoretical L value is limited to a certain range, that is, the inductance accuracy is improved, and there is no need to optimize the preparation process. On the basis of better printing quality and reproducibility of the internal electrode, the risk of leakage electrode during cutting can be reduced to meet the quality requirements of high Q value and low loss, thereby achieving an improvement in Q value. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 1 is an exploded schematic diagram of a coil structure of a multilayer chip inductor provided by an embodiment of the present invention;

[0029] Figure 2 It is a schematic diagram of a coil structure provided by an embodiment of the present invention;

[0030] Figure 3 It is a schematic diagram of a design pattern of a laminated printed sheet of a laminated chip inductor;

[0031] Figure 4 is a schematic diagram of another coil structure provided by an embodiment of the present invention;

[0032] Figure 5 is a perspective view of the overall structure of a multilayer chip inductor provided by an embodiment of the present invention;

[0033] Figure 6 FIG. 4 is a side view of the inner electrode stack of the multilayer chip inductor provided by an embodiment of the present invention.

[0034] The accompanying drawings are labeled: coil structure 100 of the lead-out layer, coil structure 200 of the first printed layer, coil structure 300 of the second printed layer, coil structure 400 of the lead-in layer, stacking unit 500, first guide hole 220, second guide hole 210, third guide hole 320, fourth guide hole 310. DETAILED DESCRIPTION

[0035] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0036] In the description of the present invention, it should be understood that descriptions involving orientation, such as up, down, left, right, etc., the orientations or positional relationships indicated are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0037] In the description of the present invention, if there is a description of first, second, etc., it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the sequence of the indicated technical features.

[0038] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0039] In the related art, refer to Figure 3 , Figure 3 It is a laminated printed sheet design pattern of a laminated sheet inductor. The corners in the pattern are right-angled as a basic example. The inductor includes a laminated printed layer with four layers as the minimum laminated structure, in a stacking order from top to bottom. The order under the minimum laminated structure is the introduction layer 1, the first printed layer 2, the second printed layer 3 and the lead-out layer 4, and the first printed layer 1 and the second printed layer 2 are satisfied as the minimum repeating unit. The laminated printed layers are provided with a coil structure printed with a conductive paste. The coil structure can be enclosed in the stacking direction to form a closed coil structure. The corners of the coil structure of the first printed layer 1 and the second printed layer 2 of the inductor are both right-angled, which makes it easy for the charge to accumulate at the corner when it flows through the right-angle structure, resulting in additional loss, increasing the error between the theoretical L value and the actual L value, and also reducing the Q value, which does not meet the use scenarios that require high-quality and high-precision inductors.

[0040] To solve the above problems, this embodiment provides a solution, please refer to Figure 1, The stacked inductor includes at least one stacked unit 500. The stacked unit 500 includes a coil structure 200 of the first printed layer and a coil structure 300 of the second printed layer (the ceramic layer is not shown in the figure). The coil structures on the printed layers are introduced as follows.

[0041] Please continue to refer to Figure 1 , The coil structure 200 of the first printed layer and the coil structure 300 of the second printed layer both include a ceramic layer and a coil structure on the ceramic layer. The projections of the adjacent upper and lower coil structures overlap to form an enclosed structure. The coil structure 200 of the first printed layer ( Figure 2 ) includes a first via 220 as the starting end and a second via 210 as the terminating end. The coil structure 300 of the second printed layer ( Figure 4 ) includes a third via 320 as the terminating end and a fourth via 310 as the starting end. The first via 220 and the third via 320 are used to connect the first printed layer and the second printed layer, and the second via 210 and the fourth via 310 are used to connect two adjacent stacked units 500.

[0042] The coil structures all include four corners, and at least one of the two corners farther from the via is an arc corner. Please refer to Figure 2 , Define the second-direction side length of the coil structure as B, the first-direction side length as A, the first-direction circumscribed side length of the arc corner θ1 as a, and the second-direction circumscribed side length as b. The first-direction circumscribed side length a of the arc corner is greater than 0 and less than or equal to half of the first-direction side length of the coil structure, that is, 0 < a ≤ 0.5A. Since the improvement in this embodiment is based on the coil structure, it is avoided that the first-direction circumscribed side length a of the arc corner exceeds half of the first-direction side length A, changing the original coil structure. At the same time, it can meet the situation where both of the two corners farther from the via are arc corners. The first direction of the coil structure refers to the dimension consistent with the width direction of the inductor, and the second direction of the coil structure refers to the dimension consistent with the length direction of the inductor. The first direction and the second direction of the coil structure are perpendicular to each other.

[0043] The second-direction circumscribed side length b of the arc corner is greater than 0 and less than or equal to half of the second-direction side length B of the coil structure, that is, 0 < b ≤ 0.5B. Similarly, it is avoided to change the original coil structure.

[0044] The angle value θ1 corresponding to the arc corner is greater than 0 and less than or equal to 2 times the arctangent function value of the smaller value of the first-direction circumscribed side length a and the second-direction circumscribed side length b divided by the larger value of the first-direction circumscribed side length a and the second-direction circumscribed side length b. According to the above conditions of 0 < a ≤ 0.5A and 0 < b ≤ 0.5B, the value range of the angle value θ1 corresponding to the arc corner can be obtained, that is (The angular value of the arc-shaped corner is the central angle corresponding to the circle where the arc is located, and the angular value is calculated according to the arc length and radius length of the arc segment).

[0045] The radius of the circle where the arc-shaped corner is located is greater than 0.5 times the square root of the sum of the squares of the outer side lengths in the second direction and the outer side lengths in the first direction of the arc-shaped corner, that is, 0.5(a 2 +b 2 ) 1 / 2 <r, which can prevent the arc-shaped corner from intersecting with the extension lines of A or B, keep the size of the inductor moderate, and limit the error value between the actual inductance value and the theoretical inductance value within a certain range, that is, reduce the error value to improve the inductance accuracy, and reduce the risk of leakage electrodes during cutting to meet the quality requirements of high Q value and low loss. If the radius is less than this range, the error value will increase and the quality will deteriorate.

[0046] The arc-shaped corner θ1 of the coil structure 200 on the first printed layer and the arc-shaped corner θ2 of the coil structure 300 on the second printed layer are at the same corner position in the stacking direction. This design corresponds to the position misalignment of corners with different shapes in the stacking direction, that is, according to the stacking order of the arc-shaped corner on the first printed layer corresponding to the right angle on the second printed layer and the right angle on the first printed layer corresponding to the arc-shaped corner on the second printed layer, it is significantly helpful for reducing the tolerance (the error between the actual inductance value and the theoretical inductance value). The comparison of different positions of the above corners will be further described in the following content.

[0047] In some embodiments, the coil structure 200 on the first printed layer and the coil structure 300 on the second printed layer are in an upper and lower surrounding structure. The side lengths of the coil structure can be unequal, and the corresponding two vias can be in a straight line position. This embodiment is easy to distinguish the positions of different shape features of the coil structure.

[0048] It can be understood that Figure 1 and Figure 2 The projection superposition of the adjacent upper and lower coil structures shown as a surrounding is only an example. This structure is not limited to long and short sides, and can also be the same side length. The positional relationship between the two vias of the same coil structure can be, but is not limited to, the upper and lower positional relationship and the left and right positional relationship.

[0049] In this embodiment, the fine-tuning of the inductance is realized through the specific design at the internal electrode corner. Without increasing or decreasing the number of stacking layers and without improving the printing requirements, a high-precision inductance value with a small tolerance can still be obtained, and the quality requirements of high Q value and low loss can be satisfied synchronously.

[0050] Refer to Figure 4As shown, the second direction side length of the same defined coil structure is C, the first direction side length is A, the first direction circumscribed side length a, the second direction circumscribed side length b, the angle value θ2 and the radius r of the arc corner, the parameter range of the arc corner θ1 of the first printing layer and the parameter range of the arc corner θ2 of the second printing layer are the same, that is, 0 <a≤0.5A, The first printing layer and the second printing layer are provided with the same arc corner, which can further reduce the tolerance.

[0051] For an example of a coil configuration, see Figure 2 and Figure 4 The coil structure of the first printing layer and the second printing layer includes a first short side in the first direction, a short side in the second direction, a long side in the first direction, a long side in the second direction, and a second short side in the first direction.

[0052] The first guide hole of the first printed layer is located at one end of the first short side in the first direction, and the second guide hole of the first printed layer is located at one end of the second short side in the first direction; the coil structure of the first printed layer is formed by sequentially connecting the first guide hole, the first short side in the first direction, the short side in the second direction, the long side in the first direction, the long side in the second direction, the second short side in the first direction, and the second guide hole, and the width values ​​of the coil structure are all equal, that is, the width of each side and the width at the corner are all equal.

[0053] The third guide hole of the second printed layer is located at one end of the first short side in the first direction, and the fourth guide hole of the second printed layer is located at one end of the second short side in the first direction; the coil structure of the second printed layer is formed by sequentially connecting the fourth guide hole, the second short side in the first direction, the long side in the second direction, the long side in the first direction, the short side in the second direction, the first short side in the first direction and the third guide hole. Similarly, the width of each side of the coil structure and the width at the corner are equal.

[0054] At least one of a corner where the long side in the first direction is connected to the long side in the second direction and a corner where the long side in the first direction is connected to the short side in the second direction is an arc corner.

[0055] In some embodiments, when the corner connecting the long side A in the first direction and the long side C in the second direction is an arc-shaped corner, its corresponding angle value is θ2; when the corner connecting the long side A in the first direction and the short side B in the second direction is an arc-shaped corner, its corresponding angle value is θ1, that is, θ1 or θ2 exists on a coil structure, or θ1 and θ2 exist at the same time.

[0056] In some embodiments, when the corner connecting the long side A in the first direction and the short side B in the second direction is an arc-shaped corner, the second-direction circumscribed side length b of the arc-shaped corner is greater than 0 and is less than or equal to 0.5 times the short side B in the second direction; the radius r of the circle where the arc-shaped corner is located is less than or equal to half of the short side B in the second direction; if the radius r is greater than half the length of the short side B in the second direction, the error value between the actual inductance value and the theoretical inductance value of the obtained inductor will become larger, thereby reducing the quality coefficient.

[0057] In some embodiments, when the corner connecting the long side A in the first direction and the long side C in the second direction is an arc corner, the second direction circumscribed side length b of the arc corner is greater than 0 and less than or equal to 0.426 times the long side C in the second direction; the radius r of the circle where the arc corner is located is less than or equal to 0.426 times the long side C in the second direction; if the radius r is greater than 0.426 times the long side C in the second direction, the error between the actual inductance value and the theoretical inductance value of the obtained inductor will become larger, thereby reducing the quality coefficient. The value range of the second direction circumscribed side length b on the second direction long side C is calculated based on the same arc corner parameters between the first printing layer and the second printing layer.

[0058] In some preferred embodiments, the arc corner can be set to have a circumscribed side length a in the first direction greater than or equal to 0.1 times the long side A in the first direction, and less than or equal to 0.4 times the long side A in the first direction, that is, 0.1A≤a≤0.4A.

[0059] In some preferred embodiments, the length of the circumscribed side b in the second direction is greater than or equal to 0.065 times the short side B in the second direction, and less than or equal to 0.26 times the short side B in the second direction, that is, 0.065B≤b≤0.26B; the angle value θ1 is greater than or equal to 28 degrees, and less than or equal to 90 degrees, that is, 28°≤θ1≤90°. For the setting of the arc corner 0.1A≤a≤0.4A, 0.065B≤b≤0.26B and 28°≤θ1≤90°, the inductor tolerance can be reduced and the Q value can be improved.

[0060] In some preferred embodiments, the length of the circumscribed side b in the second direction is greater than or equal to 0.056 times the length of the long side C in the second direction, and less than or equal to 0.22 times the length of the long side C in the second direction, that is, 0.056C≤b≤0.22C; the angle value θ2 is greater than or equal to 28 degrees, and less than or equal to 90 degrees, that is, 28°≤θ2≤90°. For the arc corner, this setting of 0.1A≤a≤0.4A, 0.056C≤b≤0.22C and 28°≤θ2≤90° can reduce the inductor tolerance and improve the Q value.

[0061] In some preferred embodiments, the coil structure of the first printed layer may have two arc corners at the same time, that is, the corner connecting the long side in the first direction and the long side in the second direction and the corner connecting the long side in the first direction and the short side in the second direction in the coil structure of the first printed layer are both arc corners.

[0062] In some preferred embodiments, the coil structure of the second printed layer may have two arc corners at the same time, that is, the corner connecting the long side in the first direction and the long side in the second direction and the corner connecting the long side in the first direction and the short side in the second direction in the coil structure of the second printed layer are both arc corners.

[0063] In some embodiments, when the two arc-shaped corners θ1 and θ2 away from the guide hole exist at the same time, their size relationship can be any one of θ1>θ2, θ1<θ2 or θ1=θ2; preferably, when θ1=θ2, the performance of the inductor can be better improved.

[0064] Reference Figure 1 As shown, the position relationship of the guide holes of the first printing layer and the second printing layer is as follows: the first guide hole 220 of the first printing layer and the third guide hole 320 of the second printing layer are aligned in the stacking direction; the second guide hole 210 of the first printing layer and the fourth guide hole 310 of the second printing layer are aligned in the stacking direction.

[0065] Furthermore, the guide holes on the coil structure are circular in shape, and the first guide hole 220, the third guide hole 320, the second guide hole 210, and the fourth guide hole 310 are all perfect circles or ellipses tangent to the first short side in the first direction or the second short side edge in the first direction. By aligning the corresponding guide holes and setting the same guide hole shape, the connection between the corresponding guide holes is facilitated.

[0066] In some preferred embodiments, the coil structure has two corner edges close to the guide hole with chamfers, such as Figure 3 As shown, the chamfer is a non-arc corner structure design in which the 90-degree sharp part of the rectangle is slightly rounded. This design will not affect the inductance value and can prevent the accumulation of charge at the corner.

[0067] Reference Figure 1 As shown, the multilayer chip inductor further includes an introduction layer and an extraction layer, a plurality of stacking units 500 are arranged between the introduction layer and the extraction layer, the introduction layer and the extraction layer both include a ceramic layer and a coil structure on the ceramic layer, the starting end of the coil structure 400 on the introduction layer is connected to the second guide hole 210 of the coil structure 200 of the first printed layer, and the terminating end of the coil structure 100 on the extraction layer is connected to the fourth guide hole 310 of the coil structure 300 of the second printed layer. The internal stacking side view of the multilayer chip inductor is shown in FIG. Figure 6As shown, the connection between the lead-in layer, the stacking unit and the lead-out layer forms a closed loop, forming an inductor coil with a closed magnetic circuit. Finally, the coil is electroplated and packaged to obtain a complete laminated chip inductor, as shown in FIG. Figure 5 A perspective view of the overall structure of a multilayer chip inductor is shown.

[0068] In order to obtain the improvement effect of the arc corner design of the first printed layer and the second printed layer on the multilayer chip inductor and the influence of the parameters of the arc corner on the performance indicators of the multilayer chip inductor, the following test was performed. First, the various parameters and structures of the multilayer chip inductor of Example 1 were determined, and then by changing certain parameters and structures, multiple embodiments and comparative examples were obtained, which were compared with Example 1, and the influence of different parameters and structures on the performance indicators of the inductor were analyzed. By comparing Comparative Examples 1 and Comparative Examples 2 with the embodiments, the influence of the arc corner and the position of the arc corner on the inductor was obtained, as shown below.

[0069] The theoretical inductance of a known inductor can be calculated using formula (1).

[0070]

[0071] Where, μ0 is the vacuum permeability; μ i is the relative magnetic permeability of the ceramic material; N is the effective number of turns of the inductor internal coil; A e is the effective magnetic flux area, i.e. the area around the inductor coil; l e is the effective magnetic path length.

[0072] The actual inductance value of the inductor can be obtained by placing the sample on the fixture of the impedance analyzer, setting the test parameters to test the frequency test spectrum of 10MHz-3GHz, reading the actual L value at the corresponding frequency of 300MHz, and calculating the deviation between the actual L value and the theoretical L value = (actual L value-theoretical L value) / theoretical L value.

[0073] The Q value of the inductor can be detected by placing the sample on the fixture of the impedance analyzer, setting the test parameters to test the frequency test spectrum of 10MHz-3GHz, and reading the actual Q value at the corresponding frequency of 300MHz.

[0074] First, the embodiment 1 is determined as follows: a laminated chip inductor is set to have 24 layers, according to Figure 1 The layers are stacked in sequence and the arc corner positions are ensured to correspond in the stacking direction, namely the lead-in layer, the first printing layer, the second printing layer, ..., the first printing layer, the second printing layer, and the lead-out layer; the coil structure width is 45μm; A=300μm, B=460μm, C=540μm.

[0075] The shape of one of the two corners away from the guide hole is set to an arc corner shape with a certain angle value, specifically: the first printing layer includes θ1, a=0.40A=120μm, b=0.26B=120μm, r=0.26B=120μm, then θ1=90.00°; the second printing layer includes θ2, a=0.40A=120μm, b=0.22C=120μm, r=0.22C=120μm, then θ2=90.00°.

[0076] Embodiment 2: The difference from Embodiment 1 is that in the first printing layer and the second printing layer, a=0.1A=30 μm, θ1=θ2=28°.

[0077] Example 3: The difference from Example 1 is that in the first printing layer and the second printing layer, a=0.5A=150 μm, θ1=θ2=77°.

[0078] Example 4: The difference from Example 1 is that in the first printing layer and the second printing layer, r=0.37B=169μm, θ1=θ2=60°.

[0079] Embodiment 5: The difference from Embodiment 1 is that the second printed layer b=0.056C=30 μm, then θ2=28°;

[0080] Example 6: The difference from Example 1 is that the first printed layer b=0.065B=30 μm, then θ2=28°; the second printed layer b=0.056C=30 μm, then θ2=28°.

[0081] Example 7: The difference from Example 1 is that in the first printing layer, b=0.5B=230 μm, θ1=55°; in the second printing layer, b=0.426C=230 μm, θ2=55°.

[0082] Example 8: The difference from Example 1 is that in the first printing layer, b=0.5B=230 μm, θ1=60°; in the second printing layer, b=0.056C=30 μm, θ2=28°.

[0083] Example 9: The difference from Example 1 is that in the first printing layer, b=0.5B=230μm, θ1=55°; in the second printing layer, r=0.37B=169μm, θ2=60°.

[0084] Example 10: The difference from Example 1 is that the shapes of the two corners away from the guide hole are set to arc corner shapes with a certain angle value, specifically: the first printed layer includes θ1 and θ2 and θ1=θ2=90.00°; the second printed layer includes θ1 and θ2 and θ1>θ2, θ1=90.00°, θ2=60°.

[0085] Example 11: The difference from Example 1 is that the shapes of the two corners away from the guide hole are set to arc corner shapes with a certain angle value, specifically: the first printed layer includes θ1 and θ2 and θ1=θ2=90.00°; the second printed layer includes θ1 and θ2 and θ1<θ2, θ1=60°, θ2=90.00°.

[0086] Example 12: The difference from Example 1 is that the shapes of the two corners away from the guide hole are set to arc corner shapes with a certain angle value, specifically: the first printing layer includes θ1 and θ2 and θ1=θ2=90.00°; the second printing layer includes θ1 and θ2 and θ1=θ2=90.00°.

[0087] Comparative Example 1: The difference from Example 1 is that no arc-shaped corners are provided, and all corners are designed as right angles.

[0088] Comparative Example 2: The difference from Example 1 is that Figure 1 The layers are stacked sequentially, but the positions of the arc corners are offset in the stacking direction, that is, the stacking order is such that the arc corners correspond to the right angles, and the right angles correspond to the arc corners.

[0089] Table 1 was obtained by calculating the above embodiments and comparative examples.

[0090] Table 1

[0091]

[0092]

[0093] According to the above calculation formula for the theoretical inductance of the inductor, it is calculated that the theoretical inductance of Examples 1-9 and Comparative Examples 1 and 2 is 120 nH; the theoretical inductance of Examples 10-12 is 100 nH.

[0094] By comparing Examples 1-12, it can be seen that:

[0095] When the corner where the short side in the second direction connects the long side in the first direction is an arc-shaped corner, and the parameter range of the arc-shaped corner is 0.1A≤a≤0.4A, 0.065B≤b≤0.26B, 28°≤θ1≤90°, the tolerance of the above-mentioned inductor is smaller and the Q value is higher.

[0096] Similarly, when the corner connecting the long side in the second direction and the long side in the first direction is an arc-shaped corner, the parameter range of the arc-shaped corner is 0.1A≤a≤0.4A, 0.056C≤b≤0.22C, 28°≤θ2≤90°, a higher precision and higher quality multilayer chip inductor can be obtained.

[0097] By comparing the first printed layer and the second printed layer of Example 1 without arc-shaped corners with Examples 1-12, it can be seen that the arc-shaped corner design significantly improves the quality factor Q value of the inductor.

[0098] By comparing the different arc corner position designs of the first printed layer and the second printed layer in the stacking direction of Example 2 with Examples 1-12, it can be seen that the same arc corner position in the stacking direction significantly reduces the tolerance of the inductor.

[0099] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the above-mentioned implementation mode. Technical personnel familiar with the field can also make various equivalent deformations or substitutions without violating the spirit of the present invention. These equivalent deformations or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A multilayer chip inductor, characterized in that: include: At least one stacking unit, the stacking unit includes a first printing layer and a second printing layer, the first printing layer and the second printing layer both include a ceramic layer and a coil structure on the ceramic layer, the projections of the adjacent upper and lower coil structures overlap to form an enclosed structure, the coil structure of the first printing layer includes a first guide hole as a starting end and a second guide hole as a terminating end, and the coil structure of the second printing layer includes a third guide hole as a terminating end and a fourth guide hole as a starting end; The first guide hole and the third guide hole are used to connect the first printing layer and the second printing layer, and the second guide hole and the fourth guide hole are used to connect two adjacent stacking units; The coil structures each include four corners, and at least one of the two corners farther from the guide hole is an arc-shaped corner; The length of the circumscribed side of the arc corner in the first direction of the coil structure is greater than 0 and is less than or equal to half of the length of the side of the coil structure in the first direction; the length of the circumscribed side of the arc corner in the second direction of the coil structure is greater than 0 and is less than or equal to half of the length of the side of the coil structure in the second direction; the angle value corresponding to the arc corner is greater than 0 and is less than or equal to 2 times the value of the inverse tangent function of the smaller value of the circumscribed side of the coil structure in the first direction and the circumscribed side of the coil structure in the second direction divided by the larger value of the circumscribed side of the coil structure in the first direction and the circumscribed side of the coil structure in the second direction; the radius of the circle where the arc corner is located is greater than 0.5 times the square root of the sum of the square of the circumscribed side of the coil structure in the second direction of the arc corner and the square of the circumscribed side of the coil structure in the first direction; The arc-shaped corner of the first printing layer and the arc-shaped corner of the second printing layer are located at the same corner position in the stacking direction.

2. The multilayer chip inductor according to claim 1, characterized in that: The coil structure comprises a first short side in the first direction, a short side in the second direction, a long side in the first direction, a long side in the second direction and a second short side in the first direction; The first guide hole of the first printing layer is located at one end of the first short side in the first direction, and the second guide hole of the first printing layer is located at one end of the second short side in the first direction; The third guide hole of the second printing layer is located at one end of the first short side in the first direction, and the fourth guide hole of the second printing layer is located at one end of the second short side in the first direction.

3. The multilayer chip inductor according to claim 2, characterized in that: There is at least one arc-shaped corner between the corner where the long side in the first direction is connected to the short side in the second direction and the corner where the long side in the first direction is connected to the long side in the second direction; When the corner connecting the long side in the first direction and the short side in the second direction is an arc corner, the length of the circumscribed side in the second direction of the arc corner is greater than 0 and less than or equal to 0.5 times the short side in the second direction; the radius of the circle where the arc corner is located is less than or equal to half of the short side in the second direction; When the corner connecting the long side in the first direction and the long side in the second direction is an arc-shaped corner, the circumscribed side length in the second direction of the arc-shaped corner is greater than 0 and less than or equal to 0.426 times the long side in the second direction; the radius of the circle in which the arc-shaped corner is located is less than or equal to 0.426 times the long side in the second direction.

4. The multilayer chip inductor according to claim 2, characterized in that: When the corner connecting the long side in the first direction and the short side in the second direction is an arc-shaped corner, the second-direction circumscribed side length of the arc-shaped corner is greater than or equal to 0.065 times the short side in the second direction, and less than or equal to 0.26 times the short side in the second direction; the angle value corresponding to the arc-shaped corner is greater than or equal to 28 degrees and less than or equal to 90 degrees.

5. The multilayer chip inductor according to claim 2, characterized in that: When the corner connecting the long side in the first direction and the long side in the second direction is an arc-shaped corner, the second-direction circumscribed side length of the arc-shaped corner is greater than or equal to 0.056 times the long side in the second direction, and less than or equal to 0.22 times the long side in the second direction; the angle value corresponding to the arc-shaped corner is greater than or equal to 28 degrees and less than or equal to 90 degrees.

6. The multilayer chip inductor according to claim 1, characterized in that: The coil structure of the first printing layer has two arc-shaped corners; the coil structure of the second printing layer has two arc-shaped corners.

7. The multilayer chip inductor according to claim 6, characterized in that: The angle values ​​of the two arc-shaped corners of the coil structure of the first printing layer are equal; the angle values ​​of the two arc-shaped corners of the coil structure of the second printing layer are equal.

8. The multilayer chip inductor according to claim 1, characterized in that: In the coil structure, two corner edges close to the guide hole are chamfered.

9. The multilayer chip inductor according to claim 1, characterized in that: The multilayer chip inductor also includes an introduction layer and a lead-out layer, a plurality of the stacked units are arranged between the introduction layer and the lead-out layer, the introduction layer and the lead-out layer both include a ceramic layer and a coil structure on the ceramic layer, the starting end of the coil structure on the introduction layer is connected to the second guide hole of the coil structure of the first printed layer, and the ending end of the coil structure on the lead-out layer is connected to the fourth guide hole of the coil structure of the second printed layer.

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