JP2002093636A - Laminated inductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure capable of reducing the electric resistance of a lead conductor, thereby improving the Q-value and easily forming the lead conductor at low cost. SOLUTION: A laminated inductor has a structure, in which electrically insulating layers and conductive patterns are alternately laminated; the ends of the respective conductive patterns are connected to each other to form a coil 22 laminated in a laminated direction in a chip-shaped electrically insulating body 20; and both ends of the coil 22 are connected to external electrodes, positioned at both ends of the surface of the electrically insulating body 20 by lead conductors 24 in the electrically insulating body 20, where the direction of counterpoising of the external electrodes coincides with the axial direction of the coil 22. The lead conductor 24 is made of a member inserted after lamination and having conductivity, that is, rather than the lead conductor 24 being formed in a laminating process, it is inserted, after the lamination. Thereby, the lead conductor can be formed into a simple configuration at a low cost. Since the lead conductor has a low electrical resistance and smooth surface, it can produce an inductor having a high Q-value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil, which is buried in an electrical insulator, and wherein both ends of an internal coil are connected to an external electrode by a lead conductor, and a direction in which the external electrode faces the coil axis. TECHNICAL FIELD The present invention relates to a laminated inductor having a structure corresponding to a direction and a manufacturing method thereof. More specifically, the present invention relates to a laminated inductor in which a lead conductor is made of a conductive member inserted after lamination, and a method of manufacturing the same. This technique is not particularly limited, but is useful as, for example, an open magnetic circuit type inductor element surface-mounted on a high-frequency circuit board of a mobile communication device or the like.

[0002]

2. Description of the Related Art A laminated inductor is formed by alternately laminating an electric insulating layer and a conductor pattern, and sequentially connecting ends of each conductor pattern to form a coil (circular pattern) superimposed in the lamination direction. Is a chip component having a structure in which an external electrode connected to both ends of an internal coil is provided on the outer surface thereof in a state embedded in an electric insulator. Non-magnetic ceramics (a typical example is a dielectric ceramic) or magnetic ceramics (a typical example is a ferrite) or the like is used as a material forming the electric insulating layer.

The method of forming a laminate is roughly classified into a method in which ceramics are formed into a sheet, a conductor pattern is screen-printed thereon, and the ceramic sheets are laminated and integrated by pressure bonding (sheet laminating method). ) And a method of alternately screen-printing a ceramic pattern and a conductor pattern to laminate (print lamination method).

[0004] Next, as a method of forming a coil buried in an electric insulator, a method of sequentially printing a conductor pattern for about 1/2 turn (for example, Japanese Patent Publication No. 60-50331).
JP-A-2-135715), or a method of sequentially printing conductor patterns for about 3/4 turns
No., refer to Japanese Unexamined Patent Application Publication No. 2000-214, etc.). In any case, a coil is formed by interconnecting and stacking conductor patterns of a predetermined shape, and each conductor pattern has an adjacent structure in the laminating direction via a thin ceramic sheet.

[0005] Such laminated inductors are classified into two types depending on the relationship between the direction in which the external electrodes face each other and the direction of the coil axis (the laminating direction). The first type is a structure in which opposing directions of both external electrodes are orthogonal to the coil axis direction.
This type was conventionally common. The second type, which has been developed in recent years, has a structure in which opposing directions of both external electrodes coincide with the coil axis direction.

FIG. 12 shows an example of the second type of laminated inductor. The coil 12 is buried in the electrical insulator 10, and the surface on which the external electrodes are formed is a surface parallel to the conductor pattern forming surface of the coil (usually, at least a terminal electrode is formed on at least the bottom surface for mounting). ). In FIG. 12, the front left surface and the rear right surface correspond to the external electrode formation surface. To connect the coil conductor patterns of the lowermost layer (for example, the leftmost layer) and the uppermost layer (for example, the rightmost layer) in the laminating direction and the two external electrodes, the lead conductors 14 are laminated so as to reach the external electrodes from both ends of the coil. Do it by doing. In the case of a sheet lamination method, the lead conductor 14 can be formed by embedding a through-hole conductor in a ceramic sheet and laminating a plurality of the ceramic sheets. In the case of the printing method, a through-hole is formed by printing a ceramic pattern while leaving a portion for forming the through-hole, and then the conductor pattern is printed so as to embed a conductor paste in the through-hole. This step may be reversed. By repeating this process a predetermined number of times, the lead conductor 14 having a required length is formed.

[0007]

As described above, in the conventional multilayer inductor, since all the lead conductors are formed by a lamination method, especially when the inductance value is small and the number of coil turns is small, the long lead conductor 14 is used. Therefore, as shown in FIG. 13A, there is a problem that the number of unstable elements of connection due to a pattern shift or the like increases.

When a land pattern 16 is formed in a via hole as shown in FIG. 12B in order to solve the problem of pattern shift, unevenness is formed by the land pattern 16 in the longitudinal direction of the lead conductor. You. At a high frequency, the current flows on the surface of the conductor, so that in such a structure, the surface distance of the conductor becomes long, and there is a problem that the resistance to the current flowing on the surface at a high frequency becomes high and the Q value becomes low.

Furthermore, since these lead conductor portions have a different shrinkage ratio during firing from the ceramic portion, they cause a reduction in yield such as poor connection, and when the shrinkage ratio is to be adjusted, an additive is added to the conductor. Therefore, a further decrease in the electric resistance is inevitable.

An object of the present invention is to provide a multilayer inductor capable of reducing the electric resistance of a lead conductor and thereby improving the Q value, and a method of manufacturing the same. Another object of the present invention is to provide a multilayer inductor having a structure in which a lead conductor can be easily and inexpensively formed, and a method for manufacturing the same.

[0011]

According to the present invention, an electric insulating layer and a conductor pattern are alternately laminated, and the ends of each conductor pattern are sequentially connected to each other so as to overlap in a laminating direction in a chip-shaped electric insulator. The coil is formed, and both ends of the coil are connected to external electrodes located at both ends of the surface of the electric insulator by extraction conductors in the electric insulator, and the opposing directions of the external electrodes coincide with the coil axial direction. This is a laminated inductor having the structure described above. In the present invention, the lead conductor is made of a conductive member inserted after lamination. That is, instead of forming the lead conductor in the lamination process, after lamination,
This is the one into which a separately manufactured conductor is inserted. The present invention is characterized in this respect. By adopting such a configuration, the inductor can be formed at a low cost with a simple configuration, and an inductor having a high Q value can be obtained because the electrical resistance is low and the lead conductor is smooth.

The lead conductor is preferably arranged in a region outside the conductor pattern of the coil body (a part excluding both ends of the coil), that is, in a region inside or outside the conductor pattern forming portion of the coil body. If the lead conductor is provided outside the conductor pattern of the coil body, there is no danger of breaking through the conductor pattern of the coil body even if the lead conductor is slightly too long, and strict precision is required for the length dimensions and insertion amount of the lead conductor. This has the advantage of being eliminated.

If the thickness of the lead conductor connecting portion at the coil end is formed larger than the thickness of the conductor pattern of the coil body, the reliability of connection with the lead conductor can be further enhanced.

The lead conductor may be a metal member such as silver or copper, a sintered member of a metal powder such as silver or copper,
Alternatively, a member in which a metal layer such as silver or copper is formed on the surface of an insulator may be used. If it is a metal member, the electric resistance is low,
The Q value can be further improved. When a sintered body is formed using a resin molded body mixed with a metal powder, it becomes easy to match the shrinkage ratio and the like with the ceramic at the time of sintering, and there is no risk of crack generation. If a metal is applied or baked only on the required part of the surface of the electrical insulator, there is no danger of short-circuiting when inserting it into an inductor with low inductance, that is, with a small number of coil turns. And the process can be simplified.

In terms of the manufacturing method, a coil superposed in the laminating direction in a chip-shaped electric insulator is formed by alternately laminating an electric insulating layer and a conductor pattern and sequentially connecting ends of each conductor pattern. A structure in which lead conductors are provided from both ends of the coil to both end surfaces of the electrical insulator and connected to external electrodes formed on the both end surfaces, and the facing direction of the external electrodes coincides with the coil axial direction. I do. In the present invention, at the time of lamination, a perforated electric insulating layer is laminated so as to form a cavity for inserting a lead conductor, and after lamination, a lead conductor made of a conductive member is inserted into the cavity. Alternatively, a method may be used in which a cavity for inserting a lead conductor is formed by drilling after lamination, and a lead conductor made of a conductive member is inserted into the cavity. In them, the cavity to be formed is made larger than the lead conductor, and a member that decomposes and disappears during firing is packed and inserted into the gap between the cavity and the lead conductor, and thereafter, when fired, the lead conductor or chip body shrinks during firing. , The effect of stress applied to the substrate can be reduced, and the occurrence of cracks and the like can be prevented. If the gap is filled with a member that decomposes and disappears at the time of firing, it is possible to prevent rattling of the lead conductor at the time of insertion, thereby enabling stable production.

According to the present invention, after lamination, a lead conductor made of a conductive member may be press-fitted or driven in, or fired in a state in which a cavity for inserting the lead conductor is formed, and then fired. A method of inserting a lead conductor made of a conductive member into the cavity is also possible.

[0017]

FIG. 1 is an assembled perspective view showing an embodiment of a laminated inductor according to the present invention, showing an internal structure. In the laminated inductor, the electric insulating layers and the conductor patterns are alternately laminated, and the ends of each conductor pattern are sequentially connected to form the coil 22 superimposed in the laminating direction inside the chip-shaped electric insulator 20. Both ends of the coil 22 are connected to external electrodes located at both ends of the surface of the electric insulator by lead conductors 24, respectively, and the opposing direction of the external electrodes coincides with the axial direction of the coil.

Here, the lead conductor 24 is made of a conductive member inserted after lamination. A cavity 26 is formed in the laminated electrical insulator 20, and the lead conductor 24 is inserted into the cavity 26. Then, it is fired. Although not shown, mounting terminal electrodes are formed on both ends of the lower surface, and external electrodes are formed on both end faces (the front left face and the rear right face in FIG. 1) so as to be continuous with the terminal electrodes. You. One end of the extraction electrode 24 is connected to the extraction conductor connection portion 28 at the coil end,
The other end is exposed at the end face of the chip and is connected to the external electrode, thereby conducting the terminal electrode and the coil.

The formation of the laminate by the electric insulating layer may be a method in which ceramics are formed into a sheet shape, a conductor pattern is screen-printed thereon, and the ceramic sheets are laminated and pressure-bonded and integrated (sheet laminating method). Then, a method of laminating by alternately screen-printing a ceramic pattern and a conductor pattern (print lamination method) may be used. As the electric insulating material, a dielectric ceramic or the like which can be sintered at a low temperature by adding glass is suitable. For example, a material obtained by mixing a binder or the like with a dielectric material in which borosilicate glass and alumina are mixed is used. This material can be fired at a temperature below the melting point of silver. Silver or the like is used as a paste material for the conductor pattern. The procedure for laminating the coil body portion and the like are basically the same as those of the conventional method.

FIG. 2A is a front view of the embodiment shown in FIG. 1, and FIGS. 2B and C are end views and a front view of the assembled state. The lead conductor connecting portions 28 at both ends of the coil are formed at the center (region inside the conductor pattern forming portion of the coil body). And the lead conductor 24
Is inserted so as to penetrate the lead conductor connecting portion 28. If the lead conductor 24 is provided in a region deviating from the conductor pattern forming portion of the coil body in this way, even if the lead conductor is somewhat too long, there is no risk of breaking through the conductor pattern of the coil body, and the length of the lead conductor and insertion The advantage is that strict precision is not required for the quantity. Further, since the extraction conductor does not block the magnetic field generated from the coil, the Q value is improved.

FIG. 3 is an explanatory view showing another embodiment of the present invention. As in FIG. 2, A is a view of a state before assembly as viewed from the front, and B and C are states of an end face and a front after assembly. FIG. To simplify the description, the same reference numerals are given to portions corresponding to FIG. 1 and FIG. The lead conductor connecting portions 28 at both ends of the coil are formed at corners (regions outside the conductor pattern forming portion of the coil body). Also in this embodiment, the leading end of the lead conductor 24 is inserted so as to penetrate the lead conductor connecting portion 28. Therefore, similarly to the above-described embodiment, there is an advantage that strict precision is not required for the length dimension and the insertion amount of the lead conductor 24.

FIGS. 4A and 4B are explanatory views showing still another embodiment of the present invention. FIG. 4A is a front view of a state before assembling and FIG. 4B is a front view of a state after assembling. Basically, it is the same as FIG. 2, and corresponding portions are denoted by the same reference numerals for simplification of description. The lead conductor connecting portions 28 at both ends of the coil are formed at the center (region inside the conductor pattern forming portion of the coil body). And lead conductor 2
4 is inserted so as to penetrate the lead conductor connecting portion 28. However, in this embodiment, the thickness of the lead conductor connecting portions 28 at both ends of the coil is formed larger than the thickness of the conductor pattern of the coil body. This way,
This is preferable because the connectivity between the lead conductor connecting portion 28 and the lead conductor 24 can be improved.

If the lead conductor is provided in a region outside the conductor pattern of the coil body as in each of the above-described embodiments, FIG.
As shown in (1), even if the lead conductor is long, there is no danger of breaking through the conductor pattern of the coil body.

The structure and shape of the lead conductor are arbitrary. An example is shown in FIG. The lead conductor may be a metal member such as silver or copper, a member obtained by sintering a metal powder such as silver or copper, or a member having a metal layer such as silver or copper formed on the surface of an insulator. If it is a metal member, the electric resistance is low and the Q value can be further improved. When a resin molded body mixed with metal powder is used, it becomes a metal member by sintering, but it is easy to match the shrinkage rate during sintering with the surrounding ceramic, and eliminate the risk of cracking Can be. The shape may be a conical shape as shown in A, a round bar shape with a sharpened tip as shown in B, or the like. In the case of a conical shape as shown in A, stress is relaxed by being pushed out when the surrounding ceramic contracts. In addition, since it is finally pressed by the external electrode from behind, there is no danger of falling off. Further, as shown in C,
It may be a member made of ceramic or the like having a round bar shape with a sharpened tip, and a metal applied or baked only on a necessary portion excluding the tip portion.

FIGS. 7A and 7B show another example of the present invention, in which A is a front view of a state before assembling, and B is a front view of a state after assembling. Here, a member in which the metal 32 is applied or baked only on both sides of one round bar 30 made of ceramic or the like is used as the lead conductor 34. A hollow 36 is formed at the center of the laminated electric insulator, and the above-described lead conductor 34 is inserted. If a member is coated or baked only on the required portion of the surface of the electrical insulator in this way, there is no danger of short-circuiting even when inserted into an inductor with small inductance, that is, with a small number of coil turns, and insertion only from one side However, since it becomes feasible, the process can be simplified.

FIG. 8 is an explanatory view showing an example of the lead conductor connecting portion at the coil end. In A, the lead conductor connecting portion 28 and the coil body connecting portion 38 are connected by a single path pattern, as in the above embodiments. Basically, this is enough.
On the other hand, in B, the lead conductor connecting portion 28 and the coil body connecting portion 38 are connected by two path patterns. In this case, even if the insertion position of the lead conductor is shifted, the shortest distance to the coil main body becomes almost equal, so that there is an advantage that the inductance does not fluctuate. In the example shown in C, the lead conductor connecting portion 39 is linear. With the linear shape, the magnetic field generated from the coil can be prevented from being interrupted as much as possible, and the shortest distance to the coil body is almost equal even if the insertion position of the lead conductor is shifted, so that the inductance does not fluctuate.

FIG. 9 is an explanatory view showing an example of a laminating step of the laminated inductor according to the present invention. Here, the sheet lamination method will be described. Steps (1) to (9) described below correspond to (1) to (9) in FIG. The material of the ceramic sheet used is the glass-added dielectric ceramic as described above, and has a thickness of, for example, about 10 to 30 μm manufactured by the doctor blade method. (1) A required number of ceramic sheets 41 having a hole 40 for inserting a lead conductor at the center are laminated to a required thickness. (2) The conductor pattern 43 at the end of the coil is formed on the ceramic sheet 42 by screen printing. A lead conductor connecting portion 44 is provided at the center. If necessary, only the lead conductor connecting portion 44 is overprinted to increase the thickness. (3) The ceramic sheet 46 in which the through-hole conductor 45 is embedded is laminated.

The coil main body is formed as follows. Here, the method of laminating the U-shaped coil element patterns while rotating the direction by 90 degrees is described, but any conventionally known method may be used for this portion. (4) The U-shaped coil element pattern 48 is printed and laminated on the ceramic sheet 47. (5) The ceramic sheet 50 in which the through-hole conductor 49 is embedded is laminated. (6) The U-shaped coil element pattern 52 is printed and laminated on the ceramic sheet 51. Hereinafter, the above steps are repeated according to the required number of turns,
Form a coil body.

(7) The ceramic sheets 54 in which the through-hole conductors 53 are embedded are laminated. (8) The coil end pattern 56 is formed on the ceramic sheet 55.
Is formed by screen printing. A lead conductor connecting portion 57 is provided at the center. If necessary, the portion of the lead conductor connecting portion 57 is overprinted and thickened. (9) A required number of ceramic sheets 59 each having a hole 58 for inserting a lead conductor at the center are laminated to a required thickness.

After the whole is laminated and press-integrated as described above, a lead conductor is inserted into the cavity, or after the lead conductor is inserted, pressure-integrated and fired. Thereafter, external electrodes are formed on both end surfaces (surfaces on which the ends of the lead conductors are exposed), and mounting terminal electrodes are formed on the lower surface. In practice, such chip components are manufactured in a multi-cavity method. A block (laminated body) that is sequentially laminated vertically and horizontally using a large ceramic sheet on which a predetermined conductor pattern and through-hole conductor are formed, and then integrated under pressure
From each other to separate chips one by one. Then, after performing degreasing, firing and deburring, a conductive paste is applied to both end surfaces of the chip and baked to form necessary electrodes, which are further plated to obtain a final product.

In the above embodiment, the method of inserting the lead conductor into the cavity formed at the time of lamination is adopted, but there are other methods. An example is shown in FIG. More specifically, in the steps (1) and (9) of FIG. 9, a simple ceramic sheet having no lead conductor insertion hole is laminated to a predetermined thickness. A chip integrated and laminated in such a state is used. FIG. 10A shows a method of driving or press-fitting a lead conductor 62 having a sharp tip from both end surfaces of a chip-shaped electric insulator 60 having a laminated structure. B shows a cavity 6 with a drill 64 at both end surfaces of a chip-shaped electric insulator 60 having a laminated structure.
6 is opened, and a lead conductor 68 is inserted into the cavity 66. The method of drilling a hole is possible even after the chip is inserted.

In the case of processing a large number of pieces at once, as shown in FIG. 11, a number of lead conductors 72 may be set up on a jig 70, and a jig may be press-fitted from one side or both sides of the laminated body 74. It is. Then, it is cut and separated into individual chips.

[0033]

As described above, the present invention is a laminated inductor having a structure in which a lead conductor is inserted after lamination, so that the internal coil body and the external electrode can be connected by a smooth conductor, thereby improving the high frequency characteristics. Q value can be increased. Further, since a metal member can be used as the lead conductor, the electric resistance can be further reduced, which also contributes to the improvement of the characteristics.

Further, the process of laminating parts other than the coil body is greatly simplified, and the connection structure between the coil and the external electrode by the lead conductor can be realized at low cost and easily.

[Brief description of the drawings]

FIG. 1 is an assembled perspective view showing one embodiment of the internal structure of a multilayer inductor according to the present invention.

FIG. 2 is an explanatory view showing another embodiment of the laminated inductor according to the present invention.

FIG. 3 is an explanatory view showing still another embodiment of the multilayer inductor according to the present invention.

FIG. 4 is an explanatory view showing another embodiment of the laminated inductor according to the present invention.

FIG. 5 is an explanatory view showing still another embodiment of the multilayer inductor according to the present invention.

FIG. 6 is an explanatory view showing an example of a lead conductor.

FIG. 7 is an explanatory view showing another embodiment of the laminated inductor according to the present invention.

FIG. 8 is an explanatory diagram showing an example of a conductor pattern at a coil end.

FIG. 9 is an explanatory view showing an example of a laminating step of the laminated inductor according to the present invention.

FIG. 10 is an explanatory view showing an example of a method for inserting a lead conductor of a multilayer inductor according to the present invention.

FIG. 11 is an explanatory view showing another example of a method for inserting a lead conductor of a multilayer inductor according to the present invention.

FIG. 12 is a perspective view showing an example of the internal structure of a conventional laminated inductor.

FIG. 13 is an explanatory diagram of the internal structure of a conventional laminated inductor.

[Explanation of symbols]

 Reference Signs List 20 electrical insulator 22 coil 24 lead conductor 26 cavity 28 lead conductor connection part

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tatsuhiko Nawa 5-36-11 Shimbashi, Minato-ku, Tokyo Fuji Electric Chemical Co., Ltd. F-term (reference) 5E062 FF01 FG01 5E070 AA01 AB06 CB01 CB13

Claims (11)

[Claims] An electric insulating layer and a conductor pattern are alternately laminated, and an end of each conductor pattern is sequentially connected to form a coil superposed in a laminating direction in a chip-shaped electric insulator. Are connected to external electrodes located at both ends of the surface of the electrical insulator by extraction conductors in the electrical insulator, respectively, and the opposing direction of the external electrodes is coincident with the coil axis direction. The multilayer inductor is characterized in that the lead conductor is made of a conductive member inserted after lamination. 2. The multilayer inductor according to claim 1, wherein the lead conductor is arranged in a region inside or outside the conductor pattern forming portion of the coil body. 3. The multilayer inductor according to claim 1, wherein the thickness of the lead conductor connecting portions at both ends of the coil is formed larger than the thickness of the conductor pattern of the coil body. 4. The multilayer inductor according to claim 1, wherein the lead conductor is a metal member such as silver or copper. 5. The multilayer inductor according to claim 1, wherein the lead conductor is a sintered member of a metal powder such as silver or copper. 6. The multilayer inductor according to claim 1, wherein the lead conductor is a member having a metal layer such as silver or copper formed on a surface of an insulator. 7. An electric insulating layer and a conductor pattern are alternately laminated, and an end of each conductor pattern is sequentially connected to form a coil superposed in a lamination direction in a chip-shaped electric insulator. Leading conductors are provided from both ends to both end surfaces of the electric insulator, and are connected to external electrodes formed on the both end surfaces, so that a laminated inductor having a structure in which the facing direction of the external electrodes coincides with the coil axis direction. In the method, at the time of lamination, a perforated electric insulating layer is laminated so as to form a cavity for inserting a lead conductor, and after lamination, a lead conductor made of a conductive member is inserted into the cavity. Manufacturing method of laminated inductors. 8. An electric insulating layer and a conductor pattern are alternately laminated, and an end of each conductor pattern is sequentially connected to form a coil superposed in a laminating direction in a chip-shaped electric insulator. Leading conductors are provided from both ends to both end surfaces of the electric insulator, and are connected to external electrodes formed on the both end surfaces, so that a laminated inductor having a structure in which the facing direction of the external electrodes coincides with the coil axis direction. A method for manufacturing a multilayer inductor, comprising: forming a cavity for inserting a lead conductor by drilling after lamination, and inserting a lead conductor made of a conductive member into the cavity. 9. The lamination according to claim 7, wherein the cavity to be formed is made larger than the lead conductor, the lead conductor is inserted into a gap between the cavity and a member which decomposes and disappears during firing, and then fired. Manufacturing method of inductor. 10. An electric insulating layer and a conductor pattern are alternately laminated, and an end of each conductor pattern is sequentially connected to form a coil superposed in a lamination direction in a chip-shaped electric insulator. Leading conductors are provided from both ends to both end surfaces of the electric insulator, and are connected to external electrodes formed on the both end surfaces, so that a laminated inductor having a structure in which the facing direction of the external electrodes coincides with the coil axis direction. A method for manufacturing a laminated inductor, comprising, after laminating, press-fitting or driving in a lead conductor made of a conductive member. 11. An electric insulating layer and a conductor pattern are alternately laminated, and an end of each conductor pattern is sequentially connected to form a coil superposed in a laminating direction in a chip-shaped electric insulator. Leading conductors are provided from both ends to both end surfaces of the electric insulator, and are connected to external electrodes formed on the both end surfaces, so that a laminated inductor having a structure in which the facing direction of the external electrodes coincides with the coil axis direction. A method for producing a multilayer inductor, comprising: firing in a state where a cavity for inserting a lead conductor is formed; and thereafter inserting a lead conductor made of a conductive member into the cavity.