JP2000200855A - Pga-type wiring board, manufacture thereof and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a PGA(Pin Grid Array)-type wiring board where pins are enhanced in mounting strength, and pads are enhanced in adhesive strength to a lower resin layer. SOLUTION: A conductor layer with pads 21 is formed on the one surface of a board, a solder resist layer 22 is formed thereon, and openings 23 are cut in the surface of the solder resist layer 22 at right angles corresponding to the pads 21 so as to expand outward toward the inside of the board and to be trapezoidal in cross section. A T-shaped pin 25 with a head of large diameter is arranged with its head located inside the opening 23, and the pin 25 is fixed by solder 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PGA (Pin Grid Array) type wiring board, a method of manufacturing the same, and a semiconductor device, and more specifically, a pin serving as an external connection terminal of a plastic package such as a build-up board. The present invention relates to a technique useful for increasing the mounting strength of pins in a PGA type wiring board having a large number of standing on one surface of a board.

[0002]

2. Description of the Related Art A PGA type wiring board can take out input / output terminals in a plane, so that even if the number of terminals increases, a relatively sufficient pitch between terminals can be ensured without increasing the outer diameter of the package. Widely used from. This substrate is roughly classified into a ceramic type substrate made of a ceramic such as alumina and a plastic type substrate obtained by laminating a glass-epoxy resin composite plate or the like.

[0003] Among them, a plastic type PGA type wiring board forms a copper wiring pattern by applying a resist or etching a copper-clad resin plate (a glass-epoxy resin composite plate or the like) having a copper plate adhered to one side thereof. It is manufactured by forming a through hole in a resin plate and forming copper by plating on the inner wall surface of the resin plate with an epoxy adhesive. Since the plastic type has low heat resistance of the substrate, the head of a pin (T-shaped pin as viewed from the side) is attached to a bonding pad formed on one side of the substrate, as in the ceramic type. It cannot be joined by soldering, and becomes a soldering joint having a relatively low melting point.

That is, the conventional plastic type PG
In the case of the A-type wiring board, the pins are attached by soldering the T-shaped head portion on a pad of the board.

[0005]

As described above, in the conventional plastic type PGA type wiring board, pins are erected on the pads of the board by soldering, but the pads (usually copper foil) are Because the pad is thinly formed on the lower insulating resin, the adhesion between the pad and the resin is weak. For example, if any external force is applied to the pin in a horizontal manner, the pad can be removed with the pad still attached to the pad. There was a problem that would be.

On the other hand, a plastic type PGA type wiring board is formed by forming an insulating film or wiring on a core substrate such as a glass-epoxy substrate or the like with a resin such as an epoxy resin, copper plating, or copper foil to form a multilayer wiring. Although there is a build-up multilayer board with a structure, especially in such a build-up multilayer board,
The problem that adhesion between the pad and the resin was weak was remarkable.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and in addition to increasing the pin mounting strength, has also improved the adhesion strength between the pad and the resin under the pad.
PG that can contribute to the improvement of connection reliability
It is an object of the present invention to provide an A-type wiring board, a method for manufacturing the same, and a semiconductor device.

[0008]

According to an embodiment of the present invention, there is provided a conductor having a pad formed on one surface of a substrate and electrically connected to a wiring pattern in the substrate. A solder resist layer having a layer, an opening formed so as to cover the conductor layer, and a portion corresponding to the pad having an opening area extending toward the inside of the substrate; And a T-shaped pin having: a PGA-type wiring board, wherein the head of the pin is fixed to a pad exposed to the opening so as to be embedded in the solder.

According to another aspect of the present invention, a step of forming a conductive layer having a pad electrically connected to a wiring pattern in a substrate on one surface of the substrate, and a step of forming a solder resist layer on the conductive layer Forming an opening in a portion of the solder resist layer corresponding to the pad such that the opening area increases toward the inside of the substrate in the thickness direction of the solder resist layer; and Placing the head of a T-shaped pin having a large head in said opening;
Fixing the pins by soldering. A method for manufacturing a PGA type wiring board is provided.

According to the PGA type wiring board and the method of manufacturing the same according to the present invention, the pins are mounted in such a manner that the head of the T-shaped pin is embedded in the solder in the opening formed in the solder resist layer. Therefore, even if an external force is applied to the pins in a horizontal manner, the problem that the pins are removed together with the pads as in the related art does not occur. As described above, according to the present invention, the mounting strength of the pin can be increased. Also,
It is possible to improve the adhesive strength between the pad and the resin under the pad, thereby contributing to the improvement of the connection reliability.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A PGA type wiring board according to a first embodiment of the present invention will be described below with reference to FIGS. The steps of FIGS. 1A to 6C described below are steps for producing a build-up multilayer wiring board as a plastic package, and have six layers in the present embodiment.

First, in the first step (see FIG. 1A), a copper foil 2 having a thickness of about 12 μm is formed on both sides of a glass BT (bismaleimide-triazine) resin core substrate 1 (thickness: 0.5 mm). Form. In the next step (see FIG. 1B), the guide hole 3 and the through hole 4 (diameter 0.2 m)
m). In the next step (see FIG. 1C), a copper plating film 5 is formed on the entire surface including the inner walls of the guide holes 3 and the through holes 4 by electrolytic plating or electroless plating.
Is formed with a thickness of at least about 15 μm. In the next step (see FIG. 1D), the substrate surface is roughened (Black O
xide), the inner wall of the through hole 4 is filled with a thermosetting resin 6. Here, the treatment for roughening the substrate surface is performed in order to increase the adhesion to a film formed on the surface in a later step. In the next step (see FIG. 1E), both surfaces of the substrate are polished and flattened.

In the next step (see FIG. 2A), a dry film 7 to be used as a resist is formed on both sides of the substrate. In the next step (see FIG. 2B), the dry film 7 is patterned using a mask (not shown),
The opening 8 is formed by performing exposure and development processing. In the next step (see FIG. 2C), the opening 8 is formed by etching.
The portion of the copper plating film 5 corresponding to the region is removed. In the next step (see FIG. 2D), the dry film 7 is removed together with a mask (not shown).

In the next step (see FIG. 3A), an insulating resin layer 9 is formed on both sides of the substrate to a thickness of about 0.5 mm, and a copper foil 10 is formed on both sides thereof to a thickness of about 12 μm. I do. The copper foil 10 constitutes a conductor layer, and together with the insulating resin layer 9 thereunder constitutes one layer of the build-up multilayer wiring board. In the next step (see FIG. 3B), the copper foil 1
A process is performed to reduce the thickness of 0 from 12 μm to about 5 μm. In the next step (see FIG. 3C), a dry film 11 to be used as a resist is formed on both sides of the substrate, and further the patterning of the dry film 11 is performed using a mask (not shown). Opening 12
To form In the next step (see FIG. 3D), etching is performed, and a portion of the copper foil 1 corresponding to the area of the opening 12 is formed.
Remove 0.

In the next step (see FIG. 4A), a via hole 13 is formed in the portion of the insulating resin layer 9 corresponding to the region of the opening 12 by laser drilling. Thereafter, the dry film 11 (see FIG. 3D) is removed together with a mask (not shown), and a process (deburring, desmear) for removing resin pieces, dirt, and the like generated by the perforation process is performed. Do. In the next step (see FIG. 4B), a copper plating film 14 having a thickness of about 20 μm is formed on the entire surface including the inner wall of the via hole 13 by electrolytic plating or electroless plating. In the next step (see FIG. 4C), a dry film 15 to be used as a resist is formed on both surfaces of the substrate, and further the patterning of the dry film 15 is performed using a mask (not shown). Do. In the next step (see FIG. 4D), a pattern 16 by copper plating is formed on the entire surface including the inner wall of the via hole 13 using the dry film 15 as a mask.

In the next step (see FIG. 5A), a tin plating film 17 is formed on the entire surface using the dry film 15 as a mask. In the next step (see FIG. 5B), the dry film 15 is removed together with a mask (not shown). In the next step (see FIG. 5C), etching is performed using an alkaline solution to remove a portion of the copper pattern 16 corresponding to the region where the dry film 15 was formed. In the next step (see FIG. 5D), the tin plating film 17 is removed.

In the next step (see FIG. 6A), an insulating resin layer 18 is formed on both sides of the substrate to a thickness of about 0.5 mm, and a copper foil 19 is formed on both sides thereof to a thickness of about 12 μm. I do. The copper foil 19 constitutes a conductor layer, and together with the insulating resin layer 18 thereunder constitutes one layer of the build-up multilayer wiring board. In the next step (see FIG. 6B), the processing from the above-described step of FIG. 3B to the step of FIG. 5D is repeated to form a via hole 20, and further the via hole 20 is formed. After forming a copper pattern 21 (including a pad to which a pin is to be joined) electrically connected to the copper pattern 16 via the inner wall of the substrate, a surface treatment is performed prior to the formation of a solder resist layer in the next step. The inner diameter of the via hole 20 after pattern formation is set to be about 50 μm. In the next step (see FIG. 6C), a solder resist layer 22 made of a resin having a property of being cured by irradiation of ultraviolet (UV) is formed on both surfaces of the substrate. The thickness of the solder resist layer 22 is set so as to be a maximum of 10 μm above the copper pattern 21.

The steps shown in FIGS. 7A to 7C described below are steps for processing the solder resist layer on the side to which the pins are joined and for firmly attaching the pins, and are features of the present invention. It is a process of making. First, in the step shown in FIG. 7A, in the solder resist layer 22 on the side where the pins are joined (upper side in the illustrated example), a portion corresponding to the region of the pad (copper pattern 21) where the pins are to be joined. A reverse tapered opening 23 is formed. That is, the solder resist layer 2
The opening 23 is formed such that the opening area gradually increases toward the inside of the substrate in the thickness direction of FIG.

The opening 23 is provided with a pad (copper pattern 2).
A mask (not shown) is formed on a portion of the solder resist layer 22 other than the portion corresponding to the region 1), and the solder resist layer 22 on which the mask is formed is exposed by UV irradiation to perform a development process. It is formed by performing. That is, when UV irradiation is performed on the solder resist layer 22, the surface of the solder resist layer 22 is most strongly affected by the UV irradiation, and the influence of the UV irradiation gradually decreases toward the inside of the substrate. The part cures fastest,
Since it gradually cures toward the inside of the substrate, an opening 23 having a reverse tapered shape as shown in the figure is formed. After the formation of the opening 23, curing and UV curing are performed.

In the next step (see FIG. 7B), an appropriate amount of solder 24 is placed on the pad 21 in the inversely tapered opening 23 formed in the solder resist layer 22 and a large diameter solder is placed thereon. A T-shaped pin 25 having a head is placed with its head down. As the pin 25, a Kovar (registered trademark) plated with nickel (Ni) and gold (Au) (with a film thickness of about 2 μm for Ni and about 0.2 μm for Au) was used.

In the last step (see FIG. 7C), reflow is performed to solidify the solder 24 and fix the pin 25.
The structure finally obtained through the above steps (FIG. 7 (c)
) Is the PGA type wiring board of the first embodiment. According to the present embodiment, when attaching the pin 25 to the pad 21, the opening 23 is formed in the solder resist layer 22 in a reverse tapered shape as described above, and the reverse tapered opening 2 is formed.
In 3, the pins 25 are fixed and fixed with an appropriate amount of solder 24. That is, the head portion of the T-shaped pin 25 is firmly fixed in such a manner as to be embedded in the solder 24 at the reverse tapered opening as shown in FIG. 7C. Therefore, even if some external force is applied to the pin 25 in the horizontal direction, the problem that the pin is removed with the pad as in the related art does not occur.

As described above, according to the present embodiment, the pin 25
Mounting strength can be increased. Also, unlike the conventional structure in which the head portion of the pin directly contacts the pad, the pad 21 does not directly contact the pin 25, and therefore, regardless of the mounting state of the pin 25, the pad 21
And the adhesive strength between the insulating resin layer 18 and the lower insulating resin layer 18 can be kept high. This leads to improvement in connection reliability between the pin 25 and the substrate.

FIG. 8 shows a PGA according to a second embodiment of the present invention.
2 shows a cross-sectional structure of a type wiring board. In the above-described first embodiment, the solder 24
To fix the pin 25 (FIG. 7).
(B) and FIG. 7 (c)). In the present embodiment, as shown in FIG. 8, first, the pins 25 are fixed by reflowing to solidify the solder 24, and further reflowing is performed to form the solder 2
The pin 25 is further firmly fixed by hardening the pin 6.
Here, the melting point of the solder 24 is set higher than the melting point of the solder 26. By performing such a process, it is possible to further increase the mounting strength of the pin 25, further increase the adhesion strength between the pad 21 and the insulating resin layer 18, and further improve the connection reliability.

FIG. 9 shows a PGA according to a third embodiment of the present invention.
2 shows a cross-sectional structure of a type wiring board. As shown in the drawing, in the present embodiment, a pin 2 is attached to the structure finally obtained in the embodiment shown in FIGS. 1 to 7 (see FIG. 7C).
High heat-resistant insulating resin sheet 2 in which holes are formed in advance on the surface of the substrate on the side where
7. The pins 25 are fixed more firmly by laminating, for example, Teflon-based resin or polyphenylene ether (PPE) by vacuum thermocompression bonding or by pouring a molding resin. By performing such processing, it is possible to achieve the same effects as in the second embodiment.

FIG. 10 shows a PG according to a fourth embodiment of the present invention.
3 shows a cross-sectional structure of an A-type wiring board. As shown in the figure, in this embodiment, after fixing the pin 25 with the solder 24 in the reverse tapered opening 23 in the solder resist layer 22, the gap is filled with an underfill agent 28 such as an epoxy resin. Further, the pins 25 are more firmly fixed by being formed on the entire surface. By performing such processing, it is possible to obtain the same effects as those of the second and third embodiments.

FIG. 11 shows the PGA according to each of the embodiments described above.
It is an example of an application example of a die-type wiring board. In the illustrated example, an electronic component, a semiconductor device, or the like (semiconductor chip in the illustrated example) is provided on the surface of the PGA type wiring board (see FIG. 30) shows the configuration of a semiconductor device in which the semiconductor device is mounted. Reference numeral 31 denotes a solder bump provided on the chip 30, and 32 denotes an underfill agent such as an epoxy resin. The connection between the chip 30 and the PGA type wiring board is performed by pressing the solder bumps 31 against the conductor layer (pad 21) of the PGA type wiring board by thermocompression bonding or the like.

The semiconductor device illustrated in FIG. 11 has been described as an application example of the PGA type wiring board of the first embodiment.
Of course, the same can be applied to the other second to fourth embodiments.

[0028]

As described above, according to the present invention, the mounting strength of the pins can be increased, and the adhesion strength between the pad and the resin under the pad can be improved, so that the connection reliability can be improved. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a manufacturing process (part 1) of a PGA type wiring board according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a manufacturing step (part 2) following the manufacturing step in FIG.

FIG. 3 is a cross-sectional view showing a manufacturing step (3) following the manufacturing step in FIG. 2;

FIG. 4 is a sectional view showing a manufacturing step (part 4) following the manufacturing step in FIG. 3;

FIG. 5 is a sectional view showing a manufacturing step (part 5) following the manufacturing step of FIG. 4;

FIG. 6 is a sectional view showing a manufacturing step (part 6) following the manufacturing step in FIG. 5;

FIG. 7 is a sectional view showing a manufacturing step (part 7) following the manufacturing step in FIG. 6;

FIG. 8 is a cross-sectional view showing a structure of a PGA type wiring board according to a second embodiment of the present invention.

FIG. 9 is a cross-sectional view illustrating a structure of a PGA type wiring board according to a third embodiment of the present invention.

FIG. 10 is a cross-sectional view showing a structure of a PGA type wiring board according to a fourth embodiment of the present invention.

FIG. 11 is a cross-sectional view showing an application example of a PGA type wiring board according to each embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 18 ... Insulating resin layer 21 ... Pad (copper pattern) 22 ... Solder resist layer 23 ... Reverse tapered opening 24, 26 ... Solder 25 ... Pin 27 ... High heat resistant insulating resin sheet 28, 32 ... Underfill agent 30 ... Semiconductor chip 31 ... Solder bump

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takahiro Iijima 711, Kurita-sha, Toshida, Nagano-shi, Nagano Prefecture Inside Shinko Electric Industries Co., Ltd. Inside Electric Industry Co., Ltd.

Claims (6)

[Claims] 1. A conductor layer formed on one surface of a substrate and having a pad conducting to a wiring pattern in the substrate, and a portion formed over the conductor layer and corresponding to the pad is directed inward of the substrate. A solder resist layer having an opening formed so as to increase the opening area toward the substrate, and a T-shaped pin having a large-diameter head, wherein the head of the pin is embedded in the solder. A PGA type wiring board fixed to a pad exposed in an opening. 2. A step of forming a conductor layer having a pad conducting to a wiring pattern in the substrate on one surface of the substrate, a step of forming a solder resist layer on the conductor layer, and a step of forming the solder resist layer Forming an opening in a portion corresponding to the pad in such a manner that the opening area increases in the thickness direction of the solder resist layer toward the inside of the substrate; and a T-shaped portion having a large diameter head. Placing the head of the pin in the opening and fixing the pin with solder. 3. The method of manufacturing a PGA type wiring board according to claim 2, wherein the step of fixing the pins with the solder includes a step of supplying the solder in two separate steps. Method of manufacturing a wiring board. 4. The method of manufacturing a PGA type wiring board according to claim 2, wherein the step of fixing the pins with the solder includes, before the step, forming a hole in a location corresponding to the position of the pin in advance. A method for manufacturing a PGA type wiring board, comprising a step of laminating a heat-resistant insulating resin sheet. 5. The method of manufacturing a PGA-type wiring board according to claim 2, wherein the step of fixing the pins with the solder includes, after the step, pouring an underfill agent into a gap between the openings to solidify the pin. A method for manufacturing a PGA type wiring board, comprising: 6. The semiconductor device according to claim 1, wherein an electronic component, a semiconductor device, or the like is mounted on a surface of the PGA type wiring board opposite to a side on which the pins are provided.