JP2006229162A - Substrate and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate capable of horizontally mounting a light emitting element to be mounted later even when a tapered housing recess is formed in order to obtain a desired infrared reflectance, and a method for manufacturing the same I will provide a.
SOLUTION: An insulating base material 2 having a tapered parabolic housing recess 7 for housing a light emitting element 17, wherein at least a central portion of a bottom portion 9 of the parabolic housing recess 7 is filled with a through hole 5. It is formed of paste 6.
[Selection] Figure 1

Description

  The present invention relates to a substrate and a manufacturing method thereof.

  In recent years, infrared communication (IrDA) has attracted attention. Infrared communication is an optical communication system that can receive signals without receiving connections by receiving light signals from infrared light emitting elements with light receiving means, and with little influence from external light. Many mobile phones have been found. In addition, since the wireless electronic payment system using infrared communication has been standardized, the importance is further increased.

In such an infrared communication device, when a light emitting element that emits infrared light is provided on an insulating base material, the light emitting element is usually placed on the surface of the insulating base material. (See Patent Document 1)
JP 2001-160631 A

Further, as shown in FIG. 10, a tapered housing recess 73 that is recessed in the thickness direction is formed in the insulating base material 72 by spot facing, and then the insulating base material 72 is covered with the plating layer 3, and the housing recess 73 is formed. The light emitting element 71 is placed on the plating layer 3 on the bottom 73a of the substrate. This is intended to improve the light collection efficiency by reflecting infrared rays using the tapered inner peripheral surface 73b of the housing recess 73.
However, since the insulating base material 72 contains glass cloth and is hard, the center of the cutting blade of the counterbore processing tool that is in a state of being only in contact with the insulating base material 72 when the counterbore processing is performed is difficult to be processed. . For this reason, an uncut portion can be left at the center of the bottom 73a, and a protrusion 70 as shown in FIG. 10 may be formed. As described above, when the protrusion 70 is formed, the bottom 73a is not flat, and the plating layer 3 on the bottom 73a also has the protrusion 74 and is not flat. Therefore, the light emitting element 71 cannot be placed horizontally. End up.

  The present invention solves the problems of the prior art, and the object of the present invention is to form a taper-shaped recess in order to obtain a desired infrared reflectance. It is an object of the present invention to provide a substrate capable of horizontally mounting a light emitting element to be mounted and a manufacturing method thereof.

  In order to achieve the above object, the invention according to claim 1 is a substrate having a tapered housing recess for housing a light emitting element, wherein at least a central portion of the bottom of the housing recess fills the hole. It is formed with the made filler.

  The invention according to claim 2 is the invention according to claim 1, wherein the hole is a through hole.

  According to a third aspect of the present invention, there is provided a method for manufacturing a substrate having a tapered housing recess for housing a light emitting element, a hole forming step for forming a hole in an insulating base material, and a filler in the hole. A filling step of filling and filling the hole, and a housing recess forming step of forming the housing recess by counterboring so that the center of the bottom is located in the hole.

  According to the first aspect of the present invention, since the central portion of the bottom portion of the receiving concave portion is formed of the filler filled in the hole portion, it is easy to carry out counterbore processing, and there is no protrusion at the central portion. A flat bottom can be formed. Therefore, the light emitting element can be provided in a horizontal state at the bottom of the housing recess.

  According to the invention which concerns on Claim 2, since a hole is a through-hole, a filler can be filled into a hole, releasing the air in a hole. Therefore, the filler can be filled in the hole without any gap.

  According to the invention of claim 3, after forming a hole in the insulating base material, filling the inside with a filler and filling the hole, the insulating substrate is subjected to counterboring, so that the housing recess is formed at the center of the bottom. Is formed so as to be located in the hole. At this time, since the hole is filled with the filler, it is easy to carry out a spot facing process, and it can be formed flat without causing a projection at the center of the bottom of the housing recess. Therefore, the light emitting element can be provided in a horizontal state at the bottom of the housing recess.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to FIGS.
As shown in FIG. 1, the infrared communication module substrate 1 (substrate) of this embodiment has an insulating base material (base material) 2. The insulating base 2 is made of a composite material of resin and glass cloth, and is formed into a plate shape having a predetermined thickness by layering a glass cloth impregnated with resin.

  And the insulating base material 2 is formed with a predetermined number of tapered parabolic accommodation recesses 7 (accommodation recesses) recessed from the upper surface 2a along the thickness direction at a predetermined depth by counterbore processing. . The parabolic housing recess 7 is formed so that its diameter decreases as it goes downward, and the bottom surface 9 </ b> A of the bottom portion 9 is parallel to the top surface 2 a of the insulating substrate 2. The inner peripheral surface 7b of the parabolic accommodation recess 7 is inclined at an angle θ within a range of 40 ° to 50 ° with respect to the horizontal plane.

  In the bottom portion 9 of the parabolic housing recess 7, a cylindrical through-hole 5 (hole portion) penetrating from the bottom surface 9 </ b> A of the bottom portion 9 to the lower surface 2 b of the insulating substrate 2 in the thickness direction of the insulating substrate 2. ) Is drilled coaxially with the bottom surface 9A. The through hole 5 has a diameter smaller than the diameter of the bottom surface 9 </ b> A of the bottom portion 9. Note that if the through hole 5 is formed so as to include the central portion of the parabolic housing recess 7, it is not necessarily formed coaxially with the bottom surface 9A.

  A primary copper plating layer 3 </ b> B that forms the opening 8 of the parabolic accommodation recess 7 is formed on the upper surface 2 a of the insulating base 2. Further, a primary copper plating layer 3 </ b> A is formed on the inner peripheral surface of the through hole 5, and this primary copper plating layer 3 </ b> A is formed on the periphery of the opening of the through hole 5 in the lower surface 2 b of the insulating base 2. It is integrated with the primary copper plating layer 3C. These primary copper plating layers 3 </ b> A, 3 </ b> B, 3 </ b> C are formed with a uniform thickness, and the thickness is such that the electrical conductivity on the insulating base 2 can be ensured. At this time, the primary copper plating layer is not formed in the parabolic housing recess 7.

  The through-hole 5 is filled with a copper paste 6 (filler) made of a resin containing copper particles inside the primary copper plating layer 3A without any gaps. The upper surface 6c of the copper paste 6 is flush with the bottom surface 9A of the bottom 9 of the parabolic housing recess 7, and the bottom 9 is entirely flat. Further, the lower surface 6b of the copper paste 6 is flush with the lower surface of the primary copper plating layer 3C.

  A secondary copper plating layer 4A is integrally formed on the upper surface 6c of the copper paste 6, the inner peripheral surface 7b of the parabolic housing recess 7 and the surface of the primary copper plating layer 3B. Further, a secondary copper plating layer 4C that covers both the lower surface 6b of the copper paste 6 and the surface of the primary copper plating layer 3C is formed. These secondary copper plating layers 4A and 4C are also formed with a uniform thickness similarly to the primary copper plating layers 3A, 3B and 3C.

  Then, on the upper surface 2a side of the insulating base material 2, a nickel layer 11 and a gold plating layer 18 are laminated on the surface of the secondary copper plating layer 4A. Specifically, the nickel layer 11 is formed on the secondary copper plating layer 4 </ b> A, and the gold plating layer 18 is formed on the nickel layer 11. The thickness of the gold plating layer 18 is a thickness capable of uniformly reflecting infrared rays.

Further, on the lower surface 2b side of the insulating base 2, the primary copper plating layer 3C covering the periphery of the opening of the through hole 5 as described above, the surface of the primary copper plating layer 3C, and the lower surface 6b of the copper paste 6 A secondary copper plating layer 4C is formed on the lower surface 2b of the insulating substrate 2 so as to completely cover them.
Then, the light emitting element 17 is mounted on the gold plating layer 18 on the bottom surface 9 </ b> A of the parabolic accommodation recess 7. At this time, the wire of the light emitting element 17 is driven into the nickel layer 11 and the gold plating layer 18.

Next, a method for manufacturing the infrared communication module substrate 1 will be described.
As shown in FIG. 2, the through-hole 5 penetrating in the thickness direction is formed in the insulating base material 2 including the glass cloth by a punching method (hole forming step). A predetermined number of the through holes 5 are formed at predetermined intervals.

  And as shown in FIG. 3, the 1st copper plating process is given to the surface of the insulation base material 2 containing the internal peripheral surface of the through-hole 5 by the electroless copper plating method, and the primary copper plating layer 3 is made uniform. Form with thickness.

  Subsequently, as shown in FIG. 4, the through-hole 5 in which the primary copper plating layer 3 is formed is filled, and the copper paste 6 is filled therein (hole filling step). At this time, the copper paste 6 is filled so that the upper surface 6a and the lower surface 6b thereof are flush with the surface of the primary copper plating layer 3 applied to the upper surface 2a and the lower surface 2b of the insulating base 2.

  Next, as shown in FIG. 5, using a counterbore bit 13 (a counterbore processing tool), a counterboring process is performed in the thickness direction of the insulating base material 2 to form a parabolic housing recess 7 (a housing recess). Forming step).

  Here, the counterbore bit 13 is formed with a tip portion 13a having a substantially conical shape in a side view, and an end portion 13b extends along the axis L of the counterbore bit 13 at the tip of the tip portion 13a. It is provided perpendicular to the direction. On this end portion 13b, the intersection 13A where the axis L and the end portion 13b intersect does not coincide with the center portion of the end portion 13b in the horizontal direction, so the left and right inclined surfaces 13c and 13d at the tip 13a are horizontal surfaces. The inclination angle with respect to is different. Among these, the cutting blade 14 is provided on the inclined surface 13c side that is steeply inclined with respect to the end portion 13b. In addition, the inclination angle θ1 of the inclined surface 13c is set to 40 ° to 50 ° from the horizontal plane.

  Such a counterbore bit 13 is made perpendicular to the upper surface 2a of the insulating base 2, and the intersection 13A of the counterbore bit 13 is set at the center of the through hole 5 in the upper surface 2a, that is, the copper paste 6 Locate in the part. In this state, when the counterbore bit 13 is rotated about the axis L, the inclined surface 13c side away from the axis L rotates on the outside, and the cutting blade 14 and the end provided on the inclined surface 13c are rotated. The parabola accommodation recessed part 7 will be formed because the part 13b cuts the insulating base material 2 and the copper paste 6 in these thickness directions (accommodation recessed part formation process). At this time, the insulating base 2 and the inclined surface 13d of the counterbore bit 13 do not contact each other, and a gap is provided between them. From this gap, the insulating base material 2 is cut to a predetermined depth while discharging chips generated when the insulating base material 2 is cut with the cutting blade 14 and the end portion 13b to the upper surface 2a of the insulating base material 2 as needed. To go.

  In this way, the parabolic accommodation recess 7 as shown in FIG. 6 is formed. At this time, since the inner peripheral surface 7b of the parabolic accommodation recess 7 is formed along the inclination angle θ1 of the inclined surface 13c, the inclination angle θ2 of the inner peripheral surface 7b with respect to the horizontal plane is 40 ° to 50 °, that is, the inclination angle The inclination angle is the same as θ1. If the counterbore bit 13 having a different inclination angle is used, the inclination angle of the inner peripheral surface 7b of the parabolic accommodation recess 7 can be appropriately changed.

  The primary copper plating layer 3 cut by the formation of the parabolic accommodation recess 7 becomes the primary copper plating layer 3 </ b> B having the opening 8 of the parabolic accommodation recess 7. Further, the primary copper plating layer formed on the inner peripheral surface of the through-hole 5 that opens to the bottom surface 9 </ b> A of the parabolic housing recess 7 becomes the primary copper plating layer 3 </ b> A. The upper surface 6 c of the copper paste 6 filled in the through hole 5 presents the bottom surface 9 </ b> A of the parabolic accommodation recess 7.

  Next, as described above, the secondary copper plating layer 4 is formed by performing the second copper plating process on the insulating base material 2 on which the parabolic housing recesses 7 are formed. First, as shown in FIG. 7, the surface of the primary copper plating layer 3B formed on the upper surface 2a of the insulating base 2 and the inner peripheral surface 7b of the parabolic accommodation recess 7, that is, as shown in FIG. The insulating base material 2 exposed by the formation of the housing recess 7 and the upper surface 6c of the copper paste 6 that presents the central portion of the bottom surface 9A of the parabolic housing recess 7 are subjected to a second copper plating process to cover them. Next, a secondary copper plating layer 4A is formed. Further, a secondary copper plating layer 4 </ b> B that covers the surface of the primary copper plating layer 3 formed on the lower surface 2 b of the insulating base 2 and the lower surface 6 b of the copper paste 6 is formed. Thereby, the insulating base material 2 is completely covered with the secondary copper plating layers 4A and 4B.

  Further, as shown in FIG. 8, a nickel plating layer 11 and a gold plating layer 18 for mounting the light emitting element 17 are sequentially laminated on the upper surface 2 a side of the insulating base 2. Specifically, the nickel plating layer 11 is formed on the surface of the secondary copper plating layer 4A, and the gold plating layer 18 is formed thereon. A wire for conducting the light emitting element 17 is driven into the gold plating layer 18. Since the gold plating layer 18 is soft, it is easy to drive the wire of the light emitting element 17, but in order to improve the strength, the nickel layer 11 is formed as a base as described above.

  Further, on the lower surface 2b side of the insulating base material 2 shown in FIG. 8, the primary copper plating layer 3 and the secondary copper plating layer 4B within a predetermined range extending radially outward from the center of the opening of the through hole 5 are left. Then, the primary copper plating layer 3 and the secondary copper plating layer 4B formed in other portions are removed by etching, and the lower surface 2b of the insulating base 2 is exposed. Then, as shown in FIG. 1, on the lower surface 2 b of the insulating base 2, the primary copper plating layer 3 </ b> C covering the periphery of the opening of the through hole 5, the lower surface 6 b of the primary copper plating layer 3 </ b> C and the copper paste 6, And a secondary copper plating layer 4 </ b> C covering the surface. Here, since the plurality of through-holes 5 are formed in the insulating base material 2, the predetermined range described above includes the primary copper plating layer 3 </ b> C and the secondary copper plating layer formed at least for each through-hole 5. This is a range in which the 4Cs are not connected to each other and the through hole 5 can be completely insulated.

  In this way, primary copper plating layers 3A, 3B, 3C and secondary copper plating layers 4A, 4B are formed.

  And the resist which is photosensitive resin is apply | coated on the lower surface 2b of the insulating base material 2 so that the copper plating layers 3 and 4 in the peripheral part of the through-hole 5 may be coat | covered, and the photosensitive resist layer 12 is formed. .

  As described above, the parabola-receiving recess 7 is formed so that the center of the bottom surface 9A of the bottom 9 is located in the through hole 5, so that the center of the spot facing is the copper paste 6. It is easy and can be made into the flat bottom part 9 without a projection part in the center part. Therefore, the light emitting element 17 can be provided in a horizontal state on the bottom 9 of the parabolic accommodation recess 7. Note that the bottom portion 9 does not necessarily have to be flat as long as the light emitting element 17 can be placed horizontally on the bottom surface 9A. For example, if the placement of the light emitting element 17 is not affected, the central portion of the bottom surface 9A may be slightly recessed.

  Further, since the inner peripheral surface 7b of the parabolic housing recess 7 is inclined and the gold plating layer 18 is exposed, it efficiently collects while reflecting the scattered light that spreads to the left and right of the infrared rays emitted from the light emitting element 17. Can be lighted. Therefore, it is possible to obtain a desired reflectance of infrared rays and to radiate infrared rays uniformly and satisfactorily above the insulating substrate 2.

  Further, by forming the copper plating layers 3A, 3B, 3C, 4A, and 4B having extremely good thermal conductivity on the insulating base material 2, it is possible to dissipate heat generated from the light emitting element 17 into the atmosphere. Become. Furthermore, since these copper plating layers 3A, 3B, 3C, 4A, 4B are connected to the upper surface 2a and the lower surface 2b of the insulating base material 2 through the parabolic housing recesses 7 and the through holes 5, the heat dissipation effect is further improved. Can be made. Therefore, deterioration of the light emitting element 17 can be prevented and the life can be extended. In addition, it is possible to make it less susceptible to the influence of the insulating base material 2 that expands due to heat generation of the light emitting element 17.

  Furthermore, since the copper plating layers 3A, 3B, 3C, 4A, and 4B are formed by the electroless copper plating method, even the insulating base material 2 having a rough surface can be formed with a uniform thickness. The copper plating layers 3A, 3B, 3C, 4A, and 4B having no uneven thickness can be formed although it takes a little time compared to the case of using the electrolytic copper plating method.

  Further, by providing the through hole 5 through the insulating base material 2, the copper paste 6 can be filled into the through hole 5 while releasing the air in the through hole 5, so that there is no gap in the through hole 5. The copper paste 6 can be filled. Since this copper paste 6 contains copper particles, it has good electrical conductivity as well as thermal conductivity.

  Moreover, each through-hole 5 can be insulated with the photosensitive resist layer 12 apply | coated to the lower surface 2b side of the insulating base material 2 as mentioned above. Further, the photosensitive resist layer 12 serves as a protective layer for the copper plating layers 3A, 3B, 3C, 4A, and 4B, and oxidation of the copper plating layers 3A, 3B, 3C, 4A, and 4B can be prevented.

Note that the copper plating layers 3A, 3B, 3C, 4A, and 4B as described above need to have appropriate thicknesses for ensuring a certain level of conductivity to the light emitting element 17.
Moreover, although the lower surface 2b of the insulating base material 2 was etched, each through-hole 5 should just be insulated and the processing method is not ask | required.
Further, the through hole 5 may be formed not having to penetrate the insulating base material 2 but having a bottom portion.
In addition, in the above description, the copper paste 6 is used as the filler. However, the present invention is not limited thereto, and a resin paste or a paste containing metal powder may be used.

  In addition, in the above, the through hole 5 has a smaller diameter than the bottom surface 9A of the parabola receiving recess 7. For example, as shown in FIG. 9, the entire parabola receiving recess 7 is formed so as to be accommodated in the through hole 25. May be. That is, the through hole 25 is formed in the insulating base 2 with a diameter larger than that of the parabolic accommodation recess 7, and the primary copper plating layer 3 is applied to the surface of the insulating base 2 including the inner peripheral surface of the through hole 25. Then, after filling the through hole 25 and filling the inside with the copper paste 6 or the resin paste 25, the parabolic accommodation recess 7 is formed at the center of the through hole 25. As described above, when the copper paste 6 or the resin paste 25 is used as the filler, the secondary copper plating layer, the nickel plating layer, and the gold are formed on the surface of the insulating base material 2 including the parabolic accommodation recess 7 as described above. A plating layer is formed.

  For filling the through holes 25, it is preferable to use a resin paste having a high light emitting property. For example, a silver paste may be filled. Thereby, it is not necessary to apply the secondary copper plating layer, the nickel plating layer, and the gold plating layer as described above, and the operation becomes easy.

It is a sectional side view which shows the infrared communication module board | substrate of one Embodiment in this invention. It is a sectional side view which shows the manufacturing process of the infrared communication module board | substrate of one Embodiment in this invention. It is a sectional side view which shows the manufacturing process of the infrared communication module board | substrate of one Embodiment in this invention. It is a sectional side view which shows the manufacturing process of the infrared communication module board | substrate of one Embodiment in this invention. It is a sectional side view which shows the manufacturing process of the infrared communication module board | substrate of one Embodiment in this invention. It is a sectional side view which shows the manufacturing process of the infrared communication module board | substrate of one Embodiment in this invention. It is a sectional side view which shows the manufacturing process of the infrared communication module board | substrate of one Embodiment in this invention. It is a sectional side view which shows the manufacturing process of the infrared communication module board | substrate of one Embodiment in this invention. It is a sectional side view which shows the infrared communication module board | substrate of other embodiment in this invention. It is a sectional side view which shows the form of the conventional infrared communication module board | substrate.

Explanation of symbols

1 Infrared communication module board (board)
2 Insulating base material 5 Through hole (hole)
6 Copper paste (filler)
7 Parabolic receiving recess (receiving recess)
9 Bottom 17 Light emitting element

Claims (3)

A substrate having a tapered housing recess for housing a light emitting element,
At least the center part of the bottom part of the said accommodating recessed part is formed with the filler with which the hole part was filled, The board | substrate characterized by the above-mentioned.     The substrate according to claim 1, wherein the hole is a through hole. In a method for manufacturing a substrate having a tapered housing recess for housing a light emitting element,
A hole forming step for forming a hole in the insulating substrate;
Filling a hole by filling the hole with a filler;
And a housing recess forming step of forming the housing recess by counterbore so that the central portion of the bottom portion is positioned in the hole.

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