TW201334655A - Method for forming substrate fixation hole - Google Patents

Abstract

The present invention provides a method for forming a fixation hole on the substrate of the package by inserting a pin between a substrate fixation hole and a wiring pattern formed on the substrate surface so as to acquire a highly precise fixation hole for the substrate. Wherein an incident laser beam L is introduced to scan a filler layer 5 which is exposed to a first port pattern 8, from a first conductor pattern 6a side along the edge 8a of the first port pattern 8 so as to eliminate the filler layer 5 and form a bottomed ditch 11 with a second conductor layer 7 as its bottom. Afterwards the dummy part of the substrate 12 the region where the filler layer 5 being encircled by the bottomed ditch 11 and the region where the second conductor layer 7 being laminated are eliminated by squeezing operation thereby forming the sophisticated substrate fixation hole 10.

Description

Substrate reference hole processing method

The present invention relates to a method for processing a substrate reference hole, which is a method for processing a substrate reference hole for positioning a substrate on a substrate such as a printed wiring.

In recent years, a printed wiring board for a semiconductor package is usually provided with a through hole called a non-through hole, and the hole wall surface is not plated, and is not conductive. This through hole is an insertion hole for inserting a positioning pin for determining the position of the substrate when the substrate is cut or cut in the manufacturing process of the printed wiring board, and is used as a reference for various processes. Moreover, when an electronic component is mounted on a substrate, it can also be used as an insertion hole for setting a positioning pin for the substrate position.

In general, the non-through hole machining used as a reference is performed by a mechanical drill controlled by NC, but the deviation between the non-through hole and the wiring pattern is 50 μm or more. If the deviation of the substrate shape or the slitting process from the wiring pattern is smaller, the distance between the wiring pattern and the processing portion can be reduced, and the pattern can be made close to the substrate shape or the finished product size can be reduced. Moreover, in the electronic component mounting program, in order to stabilize the pattern position when the substrate is placed, it is also stable. The image recognition of the machine is easy to align. Therefore, the engineering community has required to reduce the deviation between the substrate reference hole and the wiring pattern as a processing reference.

For example, in a method of forming a through hole in a wiring substrate by laser processing, it has been proposed to superimpose a similar photomask provided with an opening according to the wiring pattern and a contact mask provided with an opening overlapping the opening. A method of opening a hole by scanning with a laser beam (Patent Document 1).

[existing technical literature]

[Patent Document 1]: JP-A-2001-127397.

The printed circuit board for packaging must have a tendency to improve the rigidity by minimizing the warpage and distortion when mounting the components, or by sizing the dimensions. Therefore, a large amount of inorganic fine particles called fillers are mixed in the substrate material, or glass fibers having a small expansion coefficient and high crystallinity are used. As a result, when the laser light is irradiated through the insertion port through the insertion pin, the processing property of the glass cloth and the resin is different, and the laser irradiation portion, particularly the resin on the hole wall surface, is in a state of being scrambled. Flat, so the size of the holes is uneven. Further, in the case where the press working is performed by a metal mold, the problem of breakage or abrasion of the press is likely to occur.

Further, when the electronic component is mounted on the package substrate, the substrate must be fixed to the mold by the positioning pin. In this case, the insertion hole is often formed into a long hole in order to cope with the expansion and contraction of the substrate. The processing of the long holes on the substrate is also performed by a mechanical drill. At this time, the processing position of the drill is slightly moved to open the hole, but the system is The hole is opened in the near hole of the hole, so that the position of the drill is in contact with each other, and high-precision machining cannot be achieved. Although there is a method of using a metal mold for stamping, it is necessary to prepare an expensive metal mold. The first priority should be to form long holes with high positional accuracy at low cost.

An object of the present invention is to solve the problems of the prior art and to provide a method for processing a substrate reference hole which can maintain the rigidity required for a substrate for packaging, improve the workability of the laser light opening, and improve the substrate reference hole for substrate positioning. Positional accuracy between the wiring pattern on the surface of the substrate.

In order to attain the above object, the method for processing a substrate reference hole of the present invention has the following constitution and is characterized.

That is, the perforation is provided with an opening procedure for the substrate having the conductive layer on both sides of the insulating resin substrate; the filling agent for filling the through hole is filled to block the through hole; and the filler is ground. a program for uniformly and uniformly flattening the conductive layers formed on both surfaces of the substrate; performing electroless metal plating and electric field metal plating on both surfaces of the substrate to form a program for covering the first and second conductor layers of the filler; a step of etching the first conductive layer laminated on the filler layer to form a first conductor pattern, and forming a first opening pattern to expose the filler layer of the underlayer; and etching the second conductive layer to form an exposed portion Forming a second opening pattern of the filler layer on the bottom of the underlayer to form a second conductor pattern facing the first opening pattern; and using the first conductor layer as a mask from the first conductor layer side to emit laser light Scanning and exposing the filling to the first opening pattern along the edge of the first opening pattern Removing the agent layer to form a bottomed trench having the second conductive layer as a bottom; and pressing at least the filler layer surrounded by the bottomed trench and the substrate on which the second conductive layer is laminated The procedure of removing the substrate to form a substrate reference hole. The size and position of the reference hole of the substrate are determined by the size and position of the hole of the first conductive layer on which the first opening pattern is formed on the bottomed groove after removing the filler layer.

According to the above configuration, the first conductor layer which is laminated on the filler layer of the through-hole is formed by removing the first conductor pattern, and the first opening pattern can be formed to facilitate the processing of the substrate reference hole of a desired shape. A substrate reference hole (non-via) with a very high positional accuracy (±15 μm or less) between the wiring patterns is available. In particular, the position of the substrate reference hole depends on the size and position of the first conductor layer on which the first opening pattern is formed in the bottom groove after the removal of the filler layer, so that the positional accuracy between the substrate reference hole and the first conductor pattern can be improved.

Further, the first conductor layer is used as a mask, and the laser light is irradiated along the edge of the first opening pattern from the filler layer exposed on the first opening pattern on the first conductor layer side, thereby removing the laser beam. The bottom ditch is formed. The at least a filler layer surrounded by the bottomed trench and the unnecessary portion of the substrate on which the second conductive layer is laminated may be removed by pressing, so that a hole having a desired shape can be formed on the substrate, so that the efficiency can be improved. A circular hole, a long hole, and the like which are larger than the laser light aperture are formed.

Further, the first conductor layer on which the first opening pattern is formed is used as a mask, and the bottom groove is formed by irradiating the laser light, and the base surrounded by the bottom groove is formed. The plate does not need to be partially pressed to form the substrate reference hole, so that the hole having the same shape and design value can be obtained, and the processing purpose can be easily achieved without using a metal mold. Further, since the filler layer which is easily processed by laser is formed, the substrate reference hole wall surface is not roughened, and in addition to the formation of the wiring pattern, the substrate reference hole having excellent positional accuracy and precision is formed.

Moreover, since the bottom of the bottomed groove is used as the second conductor pattern, when the laser processing is performed, the filler layer surrounded by the bottomed groove is not peeled off from the substrate, or the falling filler layer becomes garbage. Affects the substrate processing position during the next laser processing.

The filler layer is preferably a thermosetting hole-filling ink for a filler, which is applied by a sieve method and heat-hardened. In order to improve the connection reliability of copper plating in the filled via hole, the thermosetting hole-filling ink contains inorganic particles (filler) such as cerium oxide, so that the coefficient of thermal expansion is close to that of the insulating resin substrate using glass cloth. . The filler filled in the ink usually belongs to an inorganic substance such as cerium oxide, so that the filler and the resin have a large difference in processability to the laser. However, due to the small size of the filler (for example, 50 μm or less), the field of laser processing difference is very small, so the roughness of the processed surface after laser processing is smaller than that of the substrate made of glass cloth and resin. , indicating that its processability is good.

When forming the substrate reference hole, it is preferable to minimize the size of the hole of the first conductor layer on which the first opening pattern is formed.

That is, the laser processing conditions are adjusted so that the first opening pattern is formed. The hole size of the first conductor layer is the smallest dimension of the substrate reference hole. When the insertion pin is inserted into the substrate reference hole, the opening of the first opening pattern of the smallest dimension serves as a reference. The pin for the substrate can accurately position the first conductor pattern formed on the substrate.

Preferably, the outer shape of the second conductor pattern forming the bottom of the bottom groove is formed to be larger than the outer opening pattern of the first opening pattern.

Thereby, the unnecessary portion of the substrate surrounded by the bottom groove can be easily removed by peeling off the second conductor pattern and the filler layer, or the adhesion between the filler layer and the insulating resin substrate. The so-called external dimensions are the length of the contrasting portion of the guide body pattern or the outer contour of the open pattern.

The substrate does not require a portion, and the second conductor pattern and the filler layer, or the filler layer and the insulating resin substrate may be mutually exchanged by pressing of the pressing member, application of air pressure, or application of any external force containing vibration. Stripped and removed. In this way, unnecessary portions of the substrate can be easily removed.

After forming the first opening pattern and the second conductor pattern, at least the first conductor layer is formed by laminating a nickel plating layer and a gold plating layer, and then the first conductor layer having the first opening pattern is formed as a mask to illuminate the light. The light is incident on the filler layer.

Thereby, since the reflectance of the conductor layer around the first opening pattern is increased, damage to the first conductor layer of the laser light irradiation portion and the underfill layer can be reduced, and thus the first conductor layer can be made thin.

According to the invention described above, the drilling processability of the laser light is improved while maintaining the rigidity of the package substrate, and the substrate reference hole processing with high positional accuracy is provided between the substrate positioning substrate reference hole and the wiring pattern on the substrate surface. method.

1‧‧‧Insulating resin substrate

2‧‧‧ Conductive layer (copper foil layer)

3‧‧‧Two-sided copper plate substrate

4‧‧‧through holes

5‧‧‧Fill layer

6‧‧‧1st conductor layer

6a‧‧‧1st conductor pattern

7‧‧‧2nd conductor layer

7a, 7b‧‧‧2nd conductor pattern

8‧‧‧1st opening graphic

8a‧‧‧The line of the first open figure

10‧‧‧Substrate reference hole

11‧‧‧ with bottom ditch

12‧‧‧Unwanted parts of the substrate

13‧‧‧ wiring pattern

14‧‧‧Package substrate

15‧‧‧Pressing parts

Fig. 1 is a cross-sectional view showing a substrate reference hole processing program for a package substrate.

Figure 2 is a cross-sectional photograph of the reference hole.

Embodiments of the present invention will be specifically described below with reference to the accompanying drawings.

Referring to Figures 1(A) to (J), a method of forming a reference hole on a substrate for packaging and a manufacturing procedure will be described.

As shown in Fig. 1(A), a double-sided cliche substrate 3 is prepared, and a conductive layer (copper foil layer) 2 is provided on both surfaces of an insulating resin substrate 1 (e.g., an epoxy resin substrate). On the double-sided copper plate substrate 3, a through hole 4 (opening process) is machined by a drill or the like as shown in Fig. 1(B).

Next, as shown in Fig. 1(C), a filler is applied to the through hole 4 to close it. The filler 5 is formed by coating with a hot hardenable hole-filling ink containing a filler, and then heat-hardening by a sieve method to form a filler layer 5.

Next, as shown in Fig. 1(D), the filler layer 5 is polished to completely planarize the conductive layer 2 formed on both surfaces of the substrate. As the filler, it is preferable to use a hole-filling ink which is highly filled with a filler having a fine particle diameter (for example, 50 μm or less) which is more excellent in filling and polishing properties to the through holes.

Next, as shown in the first (E) diagram, electroless copper plating and electric field copper plating are continuously applied to both surfaces of the substrate, and the first and second conductor layers 6, 7 are formed to cover the filler layer 5 and the adjacent conductive material. Two sides of layer 2 (double plating). The first and second conductor layers 6, 7 having a thickness applied to the conductor layer 2 form a first opening pattern and a second conductor pattern as described below.

Next, in the first (F) diagram, after the first and second conductor layers 6, 7 are formed, etching is performed to simultaneously form the wiring pattern and the first opening pattern 8 and the second conductor pattern 7b on both surfaces of the substrate. Specifically, after the etching mask (dry film or the like) is laminated on the first and second conductor layers 6 and 7, the wiring pattern and the first opening pattern 8 (for example, a circular shape) are exposed. Next, the second conductor pattern 7b (for example, a circular shape) is exposed, and then a pattern for forming an etching mask is developed. Thereafter, etching is performed to form the first opening pattern 8 and the second conductor pattern 7b and the first and second conductor patterns 6a and 7a. That is, the first opening pattern 8 required for processing the reference hole 10 is formed by removing the first conductor layer 6 laminated on the filler layer 5 filled in the through hole 4, thereby exposing the filler layer 5 at the bottom of the substrate. The second conductor layer 7 is removed to form a second conductor pattern 7b having a relatively large diameter. Thereby, the first opening pattern 8 and the second conductor pattern 7b can be formed simultaneously with the formation of the wiring pattern on both surfaces of the substrate.

Further, after the first and second conductor patterns 6a and 7a are formed, a nickel plating layer and a gold plating layer may be further formed on the first conductor layer 6. Taking this When the reflectance of the first conductor layer 6 around the first opening pattern 8 is increased, the first conductor layer 6 serving as the laser irradiation portion can be reduced when the laser beam is irradiated on the filler layer 5 to be described later. The damage to the underfill layer 5 and the underlying layer 1 is formed to form a thin first conductor layer 6. As a result, the thickness of the copper used to form the wiring pattern can be made thinner, and the etching of the thin wiring pattern can be applied. Further, the nickel plating layer and the gold plating layer may be formed on the side of the first conductor layer 6 on which the laser processing is performed at least, but the metal plating may be further formed on the second conductor layer 7 side.

Next, as shown in the first (G) diagram, the first conductor layer 6 is used as a mask on the filler layer 5 exposed from the first opening pattern 8 on the first conductor layer 6 side, along the first opening pattern 8. The edge portion 8a (see Fig. 1(F)) irradiates the laser light L by scanning to remove the filler layer 5, and forms the bottomed trench 11 having the second conductor pattern 7b (including the conductive layer 2) as a base. Laser light used in laser processing includes excimer lasers, YAG lasers, and carbon dioxide lasers.

Next, as shown in Fig. 1(H), this is the cross-section of the substrate after the laser processing, and the outer diameter of the second conductor pattern 7b at the bottom of the bottomed trench 11 is smaller than the outer shape of the first opening pattern 8 (inside) The diameter is large, and the outer shape (diameter) is smaller than the second conductor pattern 7b. As described above, the hole size of the substrate reference hole 10 is the smallest (outer dimension) of the first conductor layer 6 on which the first opening pattern 8 is formed. As a result, when the positioning pin is inserted into the substrate reference hole 10, the first conductor pattern 6 having the smallest diameter is formed as a reference, and the first conductor pattern 6a can be positioned with high precision.

Next, as shown in Fig. 1(I), the filler 5 surrounded by the bottom groove 11 is laminated, and the substrate (the central portion of the hole) 12 which is laminated on the second conductor layer 7 is removed by pressing. Substrate reference hole 10. The substrate unnecessary portion 12 may be subjected to the pressing of the pressing member 15 (the pressing pin), or may be applied by air pressure or any external force including vibration to cause the second conductor layer 7 and the filler layer 5 to be applied. The phase is peeled off and removed. At this time, as shown in the first (H) diagram, the second conductor pattern 7b is in a state of being laminated (adhered) to the filler layer 5 in a slightly overlapping region. Therefore, the unnecessary portion 12 of the substrate can be easily removed. Further, the second conductor pattern 7b may be laminated with the filler layer 5 and the insulating resin substrate 1 in the case of the laser processing conditions and the arrangement of the second conductor pattern 7b.

Through the above procedure, the filler layer 5 exposed to the first opening pattern 8 is irradiated with laser light to be removed, and the bottomed groove 11 having the second conductor pattern 7b as a bottom is formed, and the bottomed groove 11 is filled. The substrate layered by the agent layer 5 and the second conductor layer 7 does not need to be removed by the portion 12. As shown in the first (J) diagram, the packaging substrate 14 on which the substrate reference hole 10 and the wiring pattern 13 are simultaneously formed is completed.

Further, the conductor pattern formed by the etching is used as the mask-processed bottomed groove 11, and the layer of the filler layer 5 surrounded by the bottomed groove 11 and the substrate unnecessary portion of the second conductor layer 7 are removed by pressing. By forming the substrate reference hole 10 by this, it is possible to easily perform round hole processing, even long holes, and other hole-like processing of a desired shape without preparing an expensive metal mold.

2(a) is a substrate reference hole 10 laser for the package substrate 14 A plan view of the light incident surface side, a second half view of the substrate reference hole 10 in the second (b) and (c), and a plan view of the laser light incident surface of the substrate reference hole in the second (d) .

As shown in the second (b) and (c), by forming the filler layer 5 which is easy to be processed by laser, the hole wall surface of the substrate reference hole 10 can be prevented from being rough, and the reference hole 10 and the wiring can be formed. The pattern 14 has a good positional accuracy and is machined with a precision reference hole 10.

Further, in the present invention, although the thermosetting hole-filling ink is used as a filler, other fillers having a fine particle size filled with a high density may be used, and the penetration property, the filling property, the polishing property, and the laser processability are excellent. Insulating resin material.

1‧‧‧Insulating resin

2‧‧‧ Conductive layer

3‧‧‧Substrate

4‧‧‧through holes

5‧‧‧Fill layer

6‧‧‧1st conductor layer

6a‧‧‧1st conductor pattern

7‧‧‧2nd conductor layer

7a, 7b‧‧‧2nd conductor pattern

8‧‧‧1st opening graphic

8a‧‧‧The edge of the figure 8

L‧‧‧Laser light

10‧‧‧Substrate reference hole

11‧‧‧ with bottom ditch

12‧‧‧The substrate does not need part

13‧‧‧ wiring pattern

14‧‧‧Package substrate

15‧‧‧Pressing parts

Claims (6)

A method for processing a substrate reference hole, comprising: a hole opening process of piercing a substrate having a conductive layer on both sides of the insulating resin substrate; and filling a filling agent for filling the through hole to close the through hole a procedure of grinding the filler to uniformly and uniformly planarize the conductive layers formed on both sides of the substrate; continuously performing electroless metal plating and electric field metal plating on both sides of the substrate to form first and second conductive layers covering the filling agent; a program of a layer; a process of etching a first conductive layer laminated on the filler layer to form a first conductor pattern while forming a first opening pattern to expose the filler layer of the underlayer; etching the second conductive layer Removing the second opening pattern of the filler layer exposing the bottom of the underlayer to form a second conductor pattern facing the first opening pattern; and forming the first conductor layer from the first conductor layer side a mask that irradiates the laser beam along the edge of the first opening pattern and scans the filler layer exposed in the first opening pattern to form a bottomed groove having a bottom portion of the second conductor layer; and pressing The bottomed groove surrounds the filler is at least of the laminate layer does not need to have a substrate portion of the second conductive layer is removed, the substrate to form the group The procedure of the quasi-hole; wherein the size and position of the reference hole of the substrate are determined by the size and position of the hole of the first conductive layer on which the first opening pattern is formed on the bottomed trench after removing the filler layer. The method for processing a substrate reference hole according to the first aspect of the invention, wherein the filler layer is formed by using a hot hardenable hole-filling ink for a filler as a filler, coating by a sieve method, and heat hardening. By. The method for processing a substrate reference hole according to the first or second aspect of the invention, wherein the substrate reference hole is formed such that a size of a hole of the first conductor layer on which the first opening pattern is formed is a minimum size. The method of processing a substrate reference hole according to claim 1, wherein an outer dimension of the second conductor pattern forming the bottom of the bottomed trench is larger than an outer dimension of the first opening pattern. The method for processing a substrate reference hole according to the first aspect of the invention, wherein the substrate does not require a portion, the pressing force of the pressing member, the application of air pressure, or the application of any external force containing vibration, so that the first The 2 conductor pattern and the filler layer or the filler layer and the insulating resin substrate are peeled off from each other and removed. The method for processing a substrate reference hole according to the first aspect of the invention, after forming the first opening pattern and the second conductor pattern, forming a layer of a nickel plating layer and a gold plating layer on each of the first conductor layers, and then transmitting the layer The first opening pattern illuminates the laser light onto the filler layer.