JP2006066830A - Method of manufacturing high aspect semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the method of manufacturing a high aspect semiconductor device which can suppress a generation of warpage or the like of a substrate when forming a conductor pattern on a surface and backside of a thin substrate. <P>SOLUTION: The manufacturing method comprises the processes of preparing an insulating panel 31; forming underlying layers 60 in both surface and backside of the insulating panel 31 simultaneously, depositing a resist layer 61 in electrodeposition to the underlying layer 60 in piles, exposing the underlying layer 60 according to the formed pattern by performing a pattern forming by exposing the resist layer 61, developing the resist layer 61, forming a plating layer 62 for coil conductor with respect to the exposed underlying layer 60, removing the resist layer 61; removing the exposed underlying layers 60 in the surface and backside after having removed the resist layer, and forming a coil conductor 34 by continuously performing electric copper plating to the plating layers 62 for the coil conductor which have been formed in the surface and backside. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a high aspect conductor device.

A method for manufacturing a thin film coil by performing desired coil pattern plating on a substrate is disclosed in Patent Document 1 below. According to the description of Patent Document 1 below, a desired coil pattern plating is performed by exposing a thin film to a desired pattern on one surface of an insulating substrate made of quartz and applying electroplating to the exposed pattern. To manufacture thin film coils.
JP 58-12315 A

  The manufacturing method described in Patent Document 1 employs a single-sided process for forming a coil pattern on one side of an insulating substrate. However, if a coil pattern is formed on both the front and back surfaces of a thin substrate of about 60 μm, a single-side process is adopted, and after forming a coil pattern on one surface, the coil pattern is formed on the other surface. The stress generated inside becomes uneven. Therefore, warpage, undulation, and unevenness of the substrate may occur. In particular, when a pattern is formed on a thin flexible substrate, called a high aspect conductor, having a narrow width and a thickness in the height direction, the substrate may be warped, swelled, or uneven. Get higher.

  Accordingly, an object of the present invention is to provide a method for manufacturing a high aspect conductor device that can suppress the occurrence of warpage of the substrate when the conductor pattern is formed on the front and back surfaces of the thin substrate.

  The method of manufacturing a high aspect conductor device of the present invention includes a step of preparing a flexible substrate having holes formed therein, a step of simultaneously forming an underlayer on both the front surface and the back surface of the substrate, And a step of simultaneously depositing a resist layer on the underlying layer formed on each of the back surface and the resist layer formed on each of the front surface and the back surface, and exposing the resist layer to each other so as to surround the hole. Patterning and exposing the underlayer according to the formed pattern, simultaneously developing the resist layer patterned on each of the front and back surfaces, and exposing each of the front and back surfaces Applying electrolytic copper plating to the underlying layer simultaneously to form the first electroplating layer, and the resist layer formed on the front and back surfaces respectively The step of removing the resist layer simultaneously, the step of removing the underlying layer exposed on the front and back surfaces at the same time, and the first electroplating layer formed on the front and back surfaces simultaneously, respectively. And a step of forming a second electroplating layer by applying electrolytic copper plating.

  According to the method for producing a high aspect conductor device of the present invention, layered elements such as an underlayer, a resist layer, and each plating layer can be simultaneously formed on the front and back surfaces of the substrate in each step of producing the high aspect conductor device.

  According to the present invention, when the electroplating layer as the conductor pattern is formed on the front and back surfaces of the thin and flexible substrate, both are formed at the same time, so that it is possible to balance the stress in the substrate. A high aspect conductor device can be manufactured while suppressing the occurrence of warpage or the like.

  The knowledge of the present invention can be easily understood by considering the following detailed description with reference to the accompanying drawings shown for illustration only. Subsequently, embodiments of the present invention will be described with reference to the accompanying drawings. Where possible, the same parts are denoted by the same reference numerals, and redundant description is omitted.

  A coil element according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a perspective view of a coil element 1a in the present embodiment. The coil element 1a is a surface mount type coil element. The coil element 1a includes a flat core structure 10 and external terminals 20 that are electrically connected to other substrates. The core structure 10 is composed of a bridge-type ferrite core 11 and a protruding ferrite core 12, and the bridge-type ferrite core 11 and the protruding ferrite core 12 are combined to form a flat plate shape as a whole.

  An exploded perspective view of the coil structure 10 is shown in FIG. The bridge-type ferrite core 11 includes a rectangular flat plate portion 111 and leg portions 112 extending perpendicularly to the flat plate portion 111. A pair of leg portions 112 are provided. One leg portion 112 extends from one side of the flat plate portion 111 and the other leg portion 112 extends from the side parallel to the one side in the same direction. Therefore, when the bridge-type ferrite core 11 is arranged so that the leg portion 112 stands on the protruding ferrite core 12, a gap is formed between the flat plate portion 111 of the bridge-type ferrite core 11 and the protruding ferrite core 12. .

  The protruding ferrite core 12 has a rectangular flat plate portion 121 and a protruding portion 122 protruding from the central portion of the flat plate portion 121. The protrusion 122 is a convex portion having a prismatic shape. When the core structure 10 is configured by abutting the distal end surface of the leg portion 112 of the bridge-type ferrite core 11 to the flat plate portion 121 of the protruding ferrite core 12, an outer shell portion that is substantially a closed magnetic path is configured. The protrusion 122 is arranged inside the outer shell. The detailed structure of the bridge type ferrite core 11 and the protruding type ferrite core 12 will be described later as appropriate.

  FIG. 3 shows a perspective view of the state where the external terminal 20 is removed from the state of FIG. As shown in FIG. 3, a coil substrate 30 (high aspect conductor device) is placed in a gap between the bridge type ferrite core 11 and the protruding type ferrite core 12 constituting the core structure 10, and fixed with an adhesive 40. Has been. One end face of the coil substrate 30 is exposed from the end face where the gap portion of the core structure 10 faces. On this one end surface, the insulating plate 31 (substrate), the lead-out end electrode 32, and the protective resin layer 33 are exposed. The insulating plate 31 is a substrate that becomes a core portion constituting the coil substrate 30. The lead-out end electrode 32 is electrically connected to a coil conductor, which will be described later, and is a portion that is also electrically connected to the external terminal 20 shown in FIG. The protective resin layer 33 is a resin layer provided to protect the coil substrate 30.

  The coil substrate 30 will be described with reference to FIG. FIG. 4 is a plan view of the coil substrate 30. A hole 35 is formed in the central portion of the coil substrate 30. A coil conductor 34 (second electroplating layer) is formed so as to surround the hole 35. The coil conductor 34 is formed in a spiral shape so as to surround the hole 35 outward from a portion desired for the hole 35. The coil conductors 34 are formed on both surfaces of the coil substrate 30 and are electrically connected to the lead-out end electrodes 32, respectively.

  The lead-out end electrode 32 connected to the coil conductor 34 formed on one surface of the coil substrate 30 and the lead-out end electrode 32 connected to the coil conductor 34 formed on the other surface are respectively Provided on opposite sides of the coil substrate 30. Further, the coil conductors 34 provided on both surfaces of the coil substrate 30 are electrically connected to each other by front and back contact portions 36 (contact holes) formed at the peripheral edge portion of the hole 35. Therefore, when a voltage is applied between the lead-out end electrode 32 provided on one side of the coil substrate 30 and the lead-out end electrode 32 provided on the other side, it is formed on one surface of the coil substrate 30. A current flows from the coil conductor 34 formed to the coil conductor 34 formed on the other surface.

  The protruding portion 122 of the protruding ferrite core 12 is inserted into the hole 35 of the coil substrate 30. In order to explain this situation, FIG. 5 shows a cross-sectional view in the vicinity of the protrusion 122 of the protrusion-type ferrite core 12 in FIG. As shown in FIG. 5, the protruding portion 122 of the protruding ferrite core 12 is inserted into the hole 35 of the coil substrate 30. The protruding portion 122 of the protruding ferrite core 12 is formed slightly shorter than the leg portion 112 of the bridge type ferrite core 11. Accordingly, a gap is generated between the tip of the protrusion 122 and the bridge-type ferrite core 11, and the minute gap 41 can be formed. The minute gap 41 is provided to prevent the bridge-type ferrite core 11 and the protruding ferrite core 12 from being magnetically saturated by a current flowing through the coil conductor 34 of the coil substrate 30. Since the core structure 10 has an ultra-compact shape with one side of several millimeters or less, the dimension of the minute gap 41 (distance between the tip of the protrusion 122 and the bridge-type ferrite core 11) is preferably 0. .1 to 100 μm, more preferably 0.1 to 50 μm.

  Subsequently, a method for manufacturing the coil substrate 30 will be described with reference to FIGS. 6 and 7 are views for explaining a method of manufacturing the coil substrate 30 and illustrate a cross section of a portion corresponding to a part of the coil substrate 30. FIG. First, the insulating plate 31 is prepared (see FIG. 6A). It is assumed that the insulating plate 31 has a thickness of 60 μm, a glass cloth is impregnated with BT resin, and a hole 35 is already formed (not shown in FIG. 6).

  Subsequently, the base layer 60 is simultaneously formed on the front and back surfaces of the insulating plate 31 by electroless plating (see FIG. 6B). A photoresist layer 61 (resist layer) is simultaneously electrodeposited on each of the underlying layers 61 formed simultaneously on the front and back surfaces of the insulating plate 31 (see FIG. 6C). In the photoresist layer 61 formed on the front and back surfaces, exposure is performed on each side of the front and back surfaces by photolithography along the pattern on which the coil conductor (see FIG. 4) is to be formed, and then development is performed simultaneously on the front and back surfaces. Then, a removal portion 611 is formed (see FIG. 6D).

  Using the patterned photoresist layer 61 as a plating mask, a portion corresponding to the removal portion 611 in FIG. 6D is selectively subjected to electrolytic plating to simultaneously coat both the front and back surfaces of the coil conductor plating layer 62. (First electroplating layer) is formed (see FIG. 7A). After the coil conductor plating layer 62 is formed, the photoresist layer 61 as a plating mask is peeled and removed simultaneously on both the front and back surfaces (see FIG. 7B).

  From the state shown in FIG. 7B, the base layer 60 other than the portion where the coil conductor plating layer 62 is formed is removed by etching, and the base portion 60a is removed from the coil conductor plating layer 62 and the insulating plate 31. (See FIG. 7C).

  Thereafter, the coil conductor plating layer 62 is further grown and formed by electrodeposition by an electrolytic plating method without a selective plating mask. Thereby, a sufficiently thick conductor portion as the coil conductor 34 is obtained. The coil conductor 34 can be grown and formed at a high density until the gap G between adjacent coil conductors is 15 μm or less. This is because the plating layer is formed in proportion to the amount of electricity in the height direction, whereas the rate at which the plating layer is formed in the width (gap) direction becomes slower as the gap becomes narrower.

  After the formation of the coil conductor plating layer 62 is completed, the coil conductor 33 is formed on both surfaces of the insulating plate 31, and then the protective resin layer 33 (solder resist) is printed on both surfaces of the insulating plate 31. The coil substrate 30 is completed by covering and protecting the conductor 34.

  The effect of this embodiment is demonstrated. The coil substrate 30 has the coil conductor 34 in which the electroplating layer 62 is grown at a high density until the gap G between adjacent coil conductors 34 becomes 15 μm or less. Moreover, since the aspect ratio of the coil conductor (height / width of the coil conductor 34) can be set as high as about 0.2 to 5, the direct current resistance can be reduced to about 0.01 to 10 ohms. Accordingly, the present invention can be applied to a coil element for a power source having a large current flowing in the coil conductor 34, and the coil substrate 30 as a high aspect conductor device can be provided.

  An example in the case of concretely implementing this embodiment will be described. A BT resin substrate (a flexible soft substrate in which glass cloth is impregnated with bismaleide triazine) having a contact hole and a hole for penetrating a protrusion and having a thickness of 60 μm is prepared. A Cu film having a thickness of 0.5 μm was electrolessly plated on the front and back surfaces of the BT resin substrate to form an underlayer.

Next, a photosensitive electrodeposition resist was formed on both sides simultaneously by an electrodeposition method. Subsequently, a spiral pattern serving as a coil conductor was formed on both surfaces of the BT resin substrate by photolithography. Electroplating was performed on the patterned BT resin substrate for about 20 minutes at a current density of 15 A / dm ² or less. FIG. 8 shows a configuration of a film forming apparatus 8 used when forming an electrolytic plating film. The film forming apparatus 8 has a liquid tank 81, and a plating solution is placed in the liquid tank 81. A plating jig 82 for holding a wafer 83 on which an electrolytic plating film is formed is disposed in the liquid tank 81. The plating jig 82 is provided with a jig shielding plate 821 to shield the outer peripheral portion of the wafer 83. A pair of anodes 84 is provided so as to sandwich the plating jig 82. An outer shielding plate 85 and a stirring grid 86 are provided between the plating jig 82 and the pair of anodes 84, respectively. Since a predetermined voltage is applied between the plating jig 82 and the pair of anodes 84, it is possible to simultaneously perform plating on both surfaces of the wafer 83 attached to the plating jig 82.

  In this manner, a Cu conductor pattern having a height of 20 μm, a width of 70 μm, and a gap of 30 μm was formed. The “height” and “width” are the height and width of the Cu conductor pattern, and the “gap” is the distance between adjacent Cu conductor patterns. Further, after removing the selective plating mask resist on both sides simultaneously, the underlayer is also etched on both sides simultaneously. Thereafter, a second electroplating was simultaneously performed on both sides using the apparatus shown in FIG. 8 with a predetermined current profile to form a Cu conductor pattern having a height of 80 to 100 μm, a width of 80 μm and a gap of 15 μm at the same time. This is because the plating layer is formed in proportion to the amount of electricity in the height direction, whereas the rate at which the plating layer is formed in the width (gap) direction becomes slower as the gap becomes narrower.

  The surface on which the Cu conductor pattern was formed was subjected to Cu blackening treatment, and the surface was coated with a solder ink resist to produce a wafer (coil substrate assembly) in which spiral pattern coil conductors were aligned. Further, a portion that is not required for incorporation into the ferrite substrate was cut into a slit shape using a high-precision slicer.

  Next, using a diamond wheel grindstone, on a 0.77 mm thick ferrite substrate, one is a convex pattern that is a protruding ferrite core, and the other is a concave pattern that is a bridge type ferrite core. Each was formed by precision slicer.

  Bonding the assembly of the coil substrate having the coil conductor having the processed spiral pattern and the assembly of the protruding ferrite core and the bridge-type ferrite core in an atmosphere of 150 ° C. using an epoxy adhesive. Did. The back plate portion of the protruding ferrite core of the bonded substrate was ground to a thickness of 0.77 mm with a high precision slicer, and then chipped with a dicer to produce each element.

  Then, in order to form an external terminal to be a user terminal for circuit connection, after barrel polishing, the Cu (leading end electrode) on the terminal surface is cleaned using both wet processing and dry processing, and mask sputtering is performed. Cr and Cu were continuously formed by the method. This was subjected to barrel plating of Cu, Ni, and Sn, and a surface-mounted coil element having a product size of 3 mm long × 2.6 mm wide × 0.8 mm high could be produced.

It is a figure which shows the external appearance of the coil element which is embodiment of this invention. It is a figure which shows the core structure of FIG. It is a figure which shows a mode that the external terminal was taken from the coil element of FIG. It is a top view of the coil board | substrate of FIG. It is sectional drawing in the center vicinity of the coil element of FIG. It is a figure for demonstrating the manufacturing method of the coil board | substrate of FIG. It is a figure for demonstrating the manufacturing method of the coil board | substrate of FIG. It is a figure for demonstrating the structure of the film-forming apparatus used in the suitable Example of this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1a ... Coil element, 10 ... Core structure, 11 ... Bridge type ferrite core, 12 ... Projection type ferrite core, 20 ... External terminal, 30 ... Coil board, 31 ... Insulating plate, 32 ... Derived end electrode, 33 ... Protective resin Layer, 34 ... coil conductor, 36 ... front and back contact part, 40 adhesive.

Claims (1)

Preparing a flexible substrate having holes formed therein;
Forming an underlayer simultaneously on both the front and back surfaces of the substrate;
A step of simultaneously depositing a resist layer on each of the underlayers formed on the front surface and the back surface, respectively,
Exposing the resist layer formed on each of the front surface and the back surface to form a spiral pattern surrounding the hole, and exposing the underlayer according to the formed pattern;
Simultaneously developing each of the resist layers patterned on the front surface and the back surface;
Applying electrolytic copper plating to the underlayer exposed on each of the front surface and the back surface, respectively, to form a first electroplating layer;
Removing each of the resist layers formed on the front surface and the back surface, respectively,
A step of simultaneously removing the underlayer exposed on each of the front surface and the back surface as a result of removing the resist layer; and
A step of forming a second electroplating layer by applying and growing copper electroplating simultaneously on the first electroplating layer formed on each of the front surface and the back surface;
A method of manufacturing a high aspect conductor device comprising:

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