JPS6239097A - Manufacture of metal based printed wiring board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for manufacturing a printed wiring board based on a metal substrate.

[Background technology] Metal-based printed wiring boards have excellent heat dissipation properties due to the high thermal conductivity of the base metal, and can effectively dissipate the heat generated by the electronic components mounted on them. It has come to be widely used in response to the In manufacturing this metal-based printed wiring board, a special manufacturing method is adopted to ensure electrical insulation between the base metal and the printed circuit or through-hole circuit.

That is, as shown in FIG. 5(a), through-holes 2, 2, etc. are formed in the metal substrate 1, and copper foil or the like is formed on the surface of the metal substrate 1 through the prepreg 4. The metal foils 5 are overlapped and heated and press-molded. The prepreg 4 can be obtained by using glass cloth as a base material, impregnating it with a face of thermosetting resin such as epoxy resin or phenol resin, and heating and drying it. By performing heating and pressure molding in this manner, the prepreg 4 is cured to form an insulating adhesive 7P! 6, the metal foil 5 is laminated on the metal substrate 1, and the wood @1 exuding from the prepreg 4 is connected to the through holes 2, 2 for forming through holes.
... to be filled. In this way, a wiring board 8 as shown in FIG. 5(b) is created.Next, in this wiring board 8, through holes 9 are formed by drilling in the resin 7 in each of the through holes 2 for forming through holes. As shown in FIG. 5(c), the inner diameter of the through hole 9 is set smaller than the inner diameter of the through hole 2 for through hole formation, and the inner peripheral surface of the through hole 2 for through hole formation is covered with resin 7. is in a state of being Then, gold iMs are printed wiring according to the usual method.
A circuit pattern 16 is formed by etching, and a metal plating layer 17 is formed on the inner periphery of the through hole 9 by through hole plating as shown in FIG. 5(d). In this case, the insulation between the circuit pattern 16 and the metal substrate 1 is ensured by the insulating adhesive layer 6, and the insulation between the plating of the through hole 9) and the metal substrate 1 is ensured by the resin 7. It turns out. Furthermore, it is possible to obtain a printed wiring board as a product by printing a Tsurugurenost or a symbol mark.

In manufacturing the printed wiring board in this way, insulation between the plating layer 17 of the through hole 9 and the metal substrate 1 is ensured by the resin 7 on the inner periphery of the through hole 2 for through hole formation as described above. Therefore, the through hole 9 must be provided at the center of the through hole 2 for through hole formation. Since the resin 7 has higher transparency than the metal substrate 1, the position of the through hole 9 in the through hole 2 for forming the through hole can be confirmed by visual inspection or by visual inspection with the head held up. However, is the surface of through hole 9 made of metal? i 5 and the circuit pattern 16, and the inner surface of the through hole 9 is covered with a plating layer 17.
Through hole 9 in through hole 2 for through hole formation
It is not possible to confirm the location of Therefore, due to misalignment of the drill when processing the through hole 9, the center of the through hole 9 and the center of the through hole 2 for forming the through hole are largely deviated, and the plating layer 17 on the inner surface of the through hole 9 and the center of the through hole 2 for forming the through hole are There is a part where the thickness of the resin 7 is very thin between the inner periphery of the hole 2, and this cannot be confirmed even if the electrical insulation between the plating layer 17 of the through hole 9 and the metal substrate 1 is insufficient. However, there was a problem in that there was a risk that the product would be shipped as a defective product.

[Object of the Invention] The present invention has been made in view of the above points, and provides a metal-based printed wiring board that allows easy confirmation of misalignment between through-holes and through-holes. The purpose is to provide a manufacturing method.

[Disclosure of the Invention] According to the method for manufacturing a metal-based printed wiring board according to the present invention, a through-hole 2 for through-hole formation and a through-hole 3 for detecting drill misalignment are provided in a metal substrate 1, and Metal with insulating adhesive layer 6 on the surface? i! A wiring board 8 is created by laminating F5 and filling resin 7 into the through-hole 2 for through-hole formation and the hole 3 for detecting drill deviation position, and the position of the through-hole 2 for through-hole formation and the penetration for detecting drill deviation are filled. At the position of the hole 3, a through hole 9 and a drill deviation detection hole 10 each having a smaller diameter than the diameter of the through hole 2 for through hole formation and the diameter of the drill deviation detection hole 3 are placed in the wiring board 8 at relative positions. A hole is drilled while maintaining the relationship, and a printed wiring process is performed on this wiring board 8. At the same time, the metal foil 5 is formed in the 3 portion of the through hole for detecting drill misalignment.
By checking the positional relationship between the drill deviation detection through hole 3 and the drill deviation detection hole 10 with the metal foil 5 removed, the through hole can be formed based on this positional relationship. The present invention will now be described in detail with reference to examples.

The metal substrate 1 is made of a steel plate, an iron plate, a copper plate, an aluminum plate, etc., and as shown in FIG. Holes 2.2... are bored, and the metal substrate 1 has through holes 2 for forming through holes.
A through hole 3 for detecting drill deviation is bored at an outer position of the drill. The dimensions are set to be slightly larger than the inner diameter of the drill misalignment detection through hole 3 and the inner diameter of the through hole forming through hole 2. Then, in the same manner as explained in FIG. 2(,), metallic foil 5 such as copper foil or aluminum foil is placed on the front and back surfaces of this metal substrate 1 via prepreg 4, and heated and press-formed. The metal foil 5 is attached to the metal substrate 1 by the insulating adhesive layer 6 formed by curing the resin in the prepreg 4.
At the same time, the resin 7 exuding from the prepreg 4 is filled into the through-holes 2, 2, . . . and the through-holes 3 for detecting drill deviation. In this way, Figure 1 (
A wiring board 8 as shown in b) is created. Here, when filling the resin 7 into the through-hole forming through-hole 2 and the drill misalignment detection through-hole 3, it is not necessary to completely fill the through-holes 2 and 3 with the resin 7. It is sufficient that the inner periphery is completely covered with the resin 7.

Next, by drilling, through-holes 9 are formed through the resin 7 at the through-hole forming through-holes 2, 2, and at the same time, drill-misalignment detection holes 10 are formed through the resin 7 at the through-holes 3 for detecting drill deviation. . This drilling process determines the relative positional relationship between the center positions of the through-hole forming through-holes 2, 2... and the center position of the drill misalignment detection through-hole 3 (x)! This can be done using a drill device controlled by numerical control (NC control) or the like to sequentially move the drill bit to match the A mark and the Y coordinate. That is, for example, if a drill misalignment detection hole 10 is first drilled in the drill misalignment detection through hole 3 with a drill bit, then the through hole forming through hole 2 is drilled with a drill bit as a reference.
, 2... and the center position of the drill misalignment detection through hole 3, the through hole 9 is sequentially inserted into the through hole 2 for through hole formation.
This is done by drilling holes with a drill bit.

Therefore, if the center of the drill deviation detection hole 10 provided in the first drill deviation detection through hole 3 coincides with the center of the drill deviation detection through hole 3, the through holes 9 provided in all the through hole forming through holes 2 are aligned. The center thereof coincides with the center of the through hole 2 for through hole formation. Conversely, if the center of the drill deviation detection hole 10 provided in the first drill deviation detection through hole 3 deviates from the center of the drill deviation detection through hole 3, the through holes provided in all through hole forming through holes 2 As shown in FIG. 1(C) and FIG. 2(a), the center of the hole 9 is also shifted from the center of the through hole 2 for forming a through hole. However, even if the center of the through hole 9 is shifted from the center of the through hole 3 for through hole detection, the surface of the wiring board 8 is covered with the metal M1, so this positional shift cannot be detected as it is. I can't.

Next, the wiring board 8 provided with the through holes 9, 9, . By doing so, a plating layer 17 is formed, and a printed wiring board A is produced as shown in FIG. 1(d). Also, when etching the metal foil 5, at least one side of the metal foil 5 in the area of the drill misalignment detection through hole 3 is also removed and exposed 9.
By removing the gold 14 foil 5 in this way, the resin 7 in the portion of the through hole 3 for detecting drill deviation is exposed,
By comparing the opaque metal substrates 1 and 4 with the tree N7, which is more transparent than the metal substrate 1, the positional relationship between the drill misalignment detection through hole 3 and the drill misalignment detection hole 10 is visually observed as shown in FIG. It can be confirmed by etc. Therefore, if the center of the drill misalignment detection through hole 3 and the center of the drill misalignment detection hole 10 are greatly misaligned, the center of the through hole forming through hole 2 and the center of the through hole 9 are also greatly misaligned. To reject as a defective product if there is a thin part in the resin 7 on the inner periphery of the through hole 2 for through hole formation in the hole 9 and the insulation between the plating 7 @ 17 of the through hole 9 and the metal substrate 1 is insufficient. will be possible.

In addition, gold jK in the part of the through hole 3 for detecting drill deviation.
M5 may be removed immediately after forming the through hole 9 and drill misalignment detection hole 1o in FIG. A defective formation of the through hole 9 can be detected, and unnecessary printed wiring processing can be avoided.

In addition, as shown in FIG. 4, the difference between the diameter a of the drill misalignment detection through hole 3 and the diameter
a, -b,) and the diameter a of the through hole 2 for through hole formation.
2 and the diameter b2 of the through hole 9 (a2
By setting b2) equally, a portion where the wall thickness becomes thinner on the inner periphery of the drill misalignment detection through hole 3 due to the deviation between the center of the drill misalignment detection through hole 3 and the center of the drill misalignment detection hole 10. The thickness dimension t1 of the resin 7 is determined by determining the thickness dimension t1 of the resin 7 at the part where the wall thickness becomes thinner on the inner periphery of the through-hole forming through-hole 2 due to the deviation between the center of the through-hole forming through-hole 2 and the center of the through-hole 9. The dimension t2 can be made equal to the dimension t2, and by measuring tl in the drill misalignment detection through hole 3, it is possible to know the t2 in the through hole forming through hole 2, and it is possible to understand the drilling status of the through hole 9. will be possible. For example, the diameter of the drill misalignment detection through hole 3 is 1, = 3,775 mm,
Diameter a2 of through hole 2 for forming through hole = 1, 5
mm, and the diameter of the drill deviation detection hole 10 is = 3,17
5mar, diameter b2 of through hole 9 = 0, 9 m
When set to m, drill misalignment detection through hole 3
If the thickness of the resin 7 is 0.11 at the part where the wall thickness becomes thinner on the inner periphery of the drill misalignment detection through hole 3 due to the misalignment between the center of the drill misalignment detection hole 10 and the center of the drill misalignment detection hole 10, the through hole is formed. Due to the misalignment between the center of the through hole 2 and the center of the through hole 9, the thickness t2 of the resin 7 at the inner periphery of the through hole 2 is also 0.1 mm.
That's what it is.

[Effects of the Invention] As described above, in the present invention, a through hole for forming a through hole and a through hole for detecting drill deviation are provided in a metal substrate, and a - A wiring board is created by laminating metal foils and filling the through holes for forming through holes and the through holes for detecting drill misalignment position with resin, and the positions of the through holes for forming through holes and the positions of the through holes for detecting drill misalignment are determined. In the wiring board, a through hole and a drill deviation detection hole each having a diameter smaller than the diameter of the through hole for through hole formation and the diameter of the drill deviation detection through hole are drilled while maintaining the relative positional relationship, We printed wiring on this wiring board and removed the metal foil in the through hole for detecting drill misalignment, so if the center of the through hole is shifted from the center of the through hole for through hole formation, The center of the drill misalignment detection hole also shifts from the center of the drill misalignment detection through hole, and the misalignment between the drill misalignment detection hole and the drill misalignment detection through hole is caused by the removal of the metal base in the drill misalignment detection through hole. By checking the misalignment between the drill misalignment detection hole and the through hole for detecting drill misalignment, the misalignment between the through hole and the through hole for through hole formation is detected and a defective product is shipped. This can prevent such things.

[Brief explanation of the drawing]

Figures 1 (, ) to (d) are cross-sectional views of each step in an embodiment of the present invention, Figure 2 is a plan view of a portion of Figure 1 (c), and Figure 3 is Figure 1 (d). ), FIGS. 4(a) and 4(b) are an enlarged sectional view and an enlarged plane sectional view of a part of another embodiment of the present invention, and FIGS. 5(a) to (d) are FIG. 3 is a cross-sectional view of a part of each process showing manufacturing of a metal-based printed wiring board. 1 is a metal substrate, 2 is a through hole for forming a through hole, 3 is a through hole for detecting drill misalignment, 4 is a prepreg, 5 is a metal foil,
6 is an insulating adhesive layer, 7 is a resin, 8 is a wiring board, 9 is a through hole, and 10 is a drill displacement detection hole.

Claims (1)

[Claims] (1) A through-hole for through-hole formation and a through-hole for detecting drill misalignment are provided on a metal substrate, and metal foil is laminated on the surface of this metal substrate via an insulating adhesive layer, and the through-hole for through-hole formation and drill misalignment are laminated on the surface of the metal substrate. A wiring board is created by filling the through holes for position detection with resin, and the diameter of the through hole for through hole formation and the drill are set on the wiring board at the position of the through hole for through hole formation and the position of the through hole for detecting drill deviation. A through-hole with a diameter smaller than that of the through-hole for misalignment detection and a drill misalignment detection hole are drilled while maintaining their relative positional relationship, and printed wiring processing is performed on this wiring board, and the drill misalignment detection through-hole is drilled. A method for manufacturing a metal-based printed wiring board, comprising removing metal foil in hole portions.