JPH05299532A - Manufacturing method of aluminum nitride multilayer circuit board - Google Patents

Abstract

PURPOSE:To provide the title manufacturing method of aluminum nitride multilayer circuit board capable of coping with a high wiring density multilayer circuit board as well as surely forming plating layers at low cost. CONSTITUTION:The plating leading-out wirings 17 connecting to metallized parts 14, 15 to be plated are provided so as to reach the side 20a of the title aluminum nitride multi-layer substrate 20. Next, the substrate outer periphery is cut off by laser beam irradiation to attain the specific contour size. After performing the cutting off step, an Al layer 21 electrically connecting to the plating leading-out wires 17 is formed on the substrate side 20a. Finally, the metallized parts 14, 15 are plated using the Al layer 21 as a plating electrode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an aluminum nitride multilayer circuit board used as a semiconductor package or the like.

[0002]

2. Description of the Related Art In recent years, due to rapid progress in semiconductor manufacturing technology, high integration and high speed operation of semiconductor chips have been promoted, and large power consumption has been promoted in some semiconductor chips. With the higher integration and higher power consumption of these semiconductor chips, the amount of heat generated from the semiconductor chips tends to increase year by year, and semiconductor chip mounting substrates and the like are required to have high heat dissipation. For such a request,
Aluminum nitride substrate has a high thermal conductivity of 5 to 10 times higher than general aluminum oxide substrates, excellent heat dissipation, high electrical insulation and low dielectric constant, and a thermal expansion coefficient of silicon single crystal. Since it is close to the above, it is attracting attention as a mounting substrate and a packaging material for highly integrated chips and high-power chips.

When a semiconductor package or the like is constructed by using an aluminum nitride substrate, usually, at the same time as the firing of the aluminum nitride substrate, a metallization layer which becomes an internal wiring layer having a required circuit pattern or a mounting portion of a semiconductor chip is formed. To form a multilayer circuit board. Then, the input / output pin is joined to the joining pad provided at one end of the internal wiring layer, and the bonding pad provided at the other end of the internal wiring layer is connected to the electrode portion of the semiconductor chip to form a semiconductor package. Constitute.

Here, since the internal wiring layer and the metallized layer to be the chip mounting portion are formed by simultaneous firing as described above, they are generally formed by using a conductor paste containing a refractory metal such as W or Mo. is doing. Since a bonding wire made of Au or the like cannot be directly bonded to such a bonding pad, it is usually necessary to form a plating layer of Ni / Au or the like on the bonding pad and the chip mounting portion. Formation of such a plating layer is generally performed as follows.

First, as shown in FIG. 6 (a), the outer shape of the aluminum nitride multilayer substrate 1 is set to be larger than a required dimension, and the outer peripheral side 1a of the multilayer substrate 1 is connected to the bonding pads 2 and the chip mounting portion 3 in advance. The plating lead-out wiring 4 thus formed is formed, and the plating electrode 5 and the plating lead-out wiring 4 provided on the outer peripheral portion 1a of the substrate are connected.
Then, after utilizing these, a plating layer 6 is formed on the bonding pad 2 and the chip mounting portion 3, and then the substrate outer peripheral portion 1a is cut as shown in FIG. Are separated to have a function as the internal wiring layer 7.

[0006]

However, in the method of forming the plating layer as described above, it is difficult to arrange the wiring for plating extraction due to the increase in the wiring density accompanying the high integration of the semiconductor chip, and it is necessary. As described above, problems such as the need to increase the outer dimensions of the substrate have occurred. On the other hand, plating is also performed by bringing the plating electrodes into contact with the input / output pins, but this method requires mounting the plating electrodes on each input / output pin.
There is a problem that it causes an increase in manufacturing cost.

From the above, it is strongly demanded that the increase of the wiring density can be dealt with easily and the plating layer can be formed at a low cost.

The present invention has been made in order to solve such a problem, and it is necessary to form a plating layer at a low cost with certainty, while taking into consideration the handling of a multilayer circuit board having a high wiring density. It is an object of the present invention to provide a method for manufacturing an aluminum nitride multilayer circuit board that enables the above.

[0009]

A method for manufacturing an aluminum nitride multilayer circuit board according to the present invention comprises a metallized portion which requires plating, and an aluminum nitride multilayer circuit board manufactured by plating the metallized portion. The plating lead-out wiring electrically connected to the metallized portion requiring the plating is provided so as to reach the end face of the aluminum nitride multilayer substrate, and the end face of the aluminum nitride multilayer substrate is irradiated with a laser, whereby The aluminum nitride multilayer circuit board is manufactured by forming an aluminum layer electrically connected to the plating lead-out wiring and using the aluminum layer as a plating electrode to plate the metallized portion.

[0010]

In the method for manufacturing an aluminum nitride multi-layer circuit board of the present invention, the aluminum nitride multi-layer board in which the plating lead-out wiring has reached the end face in advance is used, and the aluminum nitride multi-layer board is processed into a predetermined dimension or the like. The aluminum layer is formed on the end surface of the substrate by performing laser irradiation as a cutting step). Since this aluminum layer is in a state of being electrically connected to the plating lead-out wiring, it can be used as a plating electrode. As described above, by using the aluminum layer formed by laser irradiation as the plating electrode, the wiring can be easily routed, and the outer shape of the substrate can be made close to the actual size during the manufacturing process. Further, it becomes possible to simplify the structure of the plating jig. With these,
It is possible to easily manufacture a multilayer circuit board having a high wiring density at low cost.

[0011]

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

1 to 5 are views showing steps of manufacturing an aluminum nitride multilayer circuit board according to an embodiment of the present invention. First, as shown in FIG. 1, a required number of aluminum nitride green sheets 11 are prepared, and through holes 12 and the like are formed in these sheets according to the shape of each layer. Then
The pattern of the internal wiring layer 13 is formed on these green sheets 11.
The conductor paste is applied by screen printing or the like according to the pattern of the chip mounting portion 14, the bonding pad 15, the pin bonding pad 16 and the like, and the inside of the through hole 12 that connects the layers Fill the conductor paste with. As the conductor paste, a high melting point metal powder such as W or Mo, or a mixture thereof with an active metal or a compound powder thereof as required, and an organic binder mixed into a paste are used.

The internal wiring layer 13 connected to the metallized portion that requires plating, for example, the chip mounting portion 14 and the bonding pad 15 at the time of printing the above-mentioned conductor paste, serves as the plating lead-out wiring 17, one end of which is the green sheet 11 side It is formed so as to reach the end surface 11a.

After the green sheets 11 thus printed and filled with the conductor paste are laminated and integrated, a temperature corresponding to the composition of the green sheet 11 and the composition of the conductor paste, for example, 1600 ° C. to 1800. Heat treatment is performed in a non-oxidizing atmosphere such as a nitrogen atmosphere in a temperature range of about ℃, and each green sheet 11 and the conductor paste are simultaneously burned,
The aluminum nitride multilayer substrate material 18 is manufactured as shown in FIG.

Next, the outer peripheral portion 18a is cut so that the aluminum nitride multilayer substrate material 18 obtained by the co-firing has a predetermined outer dimension. This cutting is performed using a relatively high-power laser beam 19 such as a CO ₂ laser. in this way,
When cutting with the laser light 19, as shown in FIG.
The side surface 20a of the aluminum nitride multilayer substrate 20 after cutting,
That is, the Al layer 21 is deposited on the portion irradiated with the laser beam 19. The Al layer 21 is formed by vaporizing N atoms by the laser light 19 and leaving only Al uniformly.

Further, one end of the internal wiring layer 13 serves as a wiring 17 for plating lead-out, and the aluminum nitride multilayer substrate 2 is provided.
Since it is formed so as to reach the side surface 20a of No. 0, it is in a state of being electrically connected to the Al layer 21. Therefore,
The Al layer 21 formed on the side surface 20a of the aluminum nitride multilayer substrate 20 can be used as a plating electrode.

In this embodiment, the output is 0.5 to 2.0 kW.
When the outer peripheral portion 18a of the aluminum nitride multilayer substrate material 18 after the simultaneous firing was cut by irradiating the same with a CO ₂ laser, it was confirmed that the Al layer 20 was uniformly formed on the substrate side surface 20a. Also, the Al layer 21 and the chip mounting portion 1
4 and the bonding pad 15 were confirmed to be surely electrically connected to each other.

In the above description, the example in which the laser beam 19 is simply used for cutting to a predetermined outer dimension has been described, but the same applies to the case where the laser beam 19 is used for scribing in the case of taking a large number of pieces. The Al layer 21 can be formed and can be used as a plating electrode.
Further, the Al layer 21 may be formed by irradiating the side surface of the substrate with the laser beam 19 separately from the cutting or the like.

After the Al layer 21 is formed on the side surface 20a of the aluminum nitride multilayer substrate 20 in this way, the input / output pins 22 are bonded to the pin bonding pads 16 as shown in FIG. Next, the Al layer 21 on the side surface 20a of the substrate is used as a plating electrode, and the plating electrode is electrically connected to perform electroplating. Alternatively, a laminated plating layer or the like of these is formed. During this plating, the Al layer 21 serving as a plating electrode is uniformly formed on the side surface 20a of the substrate, so that the plating jig can have a simpler structure than a conventional jig.

After this, as shown in FIG.
The Al layer 21 of a is removed by end face polishing, the plating lead-out wiring 17 is electrically separated, and the original function of the internal wiring layer 13 is restored to obtain the intended aluminum nitride multilayer circuit board 24. .. Also, output 0.5 to 2.0
After the input / output pins 21 were joined by brazing to the above-mentioned aluminum nitride substrate cut by a kW CO ₂ laser, the Al layer 21 on the substrate side surface 20a was used as a plating electrode.
When Ni plating was applied under the condition of current density of 2 to 3 A / cm ² , chip mounting part 14 and each bonding pad 15
It was confirmed that a uniform Ni plating layer 23 was formed on each of the above.

As described above, in the method for manufacturing an aluminum nitride multilayer circuit board according to this embodiment, since the lead-out wiring 17 for plating need only be formed so as to reach the side surface of the board, the wiring can be easily routed. For example, a multilayer circuit board having a high wiring density can be easily manufactured. Further, since it is not necessary to separately form a plating electrode, the outer shape of the substrate can be made close to the actual size during the manufacturing process, the manufacturing cost can be reduced, and the design can be facilitated. Further, since the structure of the plating jig can be simplified, it is possible to further reduce the manufacturing cost.

[0022]

As described above, according to the method for manufacturing an aluminum nitride multilayer circuit board of the present invention, it is possible to easily route the lead wiring for plating. It becomes easy to deal with the circuit board and the like. Furthermore, the outer shape of the board during the manufacturing process can be designed to be close to the actual size, and the structure of the plating jig can be simplified. Can be manufactured.

[Brief description of drawings]

FIG. 1 is a diagram showing one manufacturing process of an aluminum nitride multilayer circuit board according to one embodiment of the present invention, and is a perspective view showing a step of stacking green sheets.

FIG. 2 is a diagram showing one manufacturing process in the example of the present invention and is a perspective view showing an aluminum nitride multilayer substrate after co-firing.

FIG. 3 is a diagram showing one manufacturing process in the embodiment of the present invention and is a perspective view showing a state in which the outer peripheral portion of the substrate is cut.

FIG. 4 is a diagram showing one manufacturing process in the example of the present invention, and is a perspective view showing an aluminum nitride multilayer substrate after plating.

FIG. 5 is a perspective view showing an aluminum nitride multilayer circuit board manufactured according to an embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a main part manufacturing process of an aluminum nitride multilayer circuit board which requires conventional plating.

[Explanation of symbols]

 11 …… Aluminum Nitride Green Sheet 12 …… Through Hole 13 …… Internal Wiring Layer 14 …… Chip Mounting Area 15 …… Bonding Pad 16 …… Pin Bonding Pad 17 …… Plating Lead-out Wiring 18 …… Nitriding After Simultaneous Firing Aluminum multilayer substrate material 19 ... Laser light 20 ... Aluminum nitride multilayer substrate 20a ... Board side 21 ... Al layer 22 ... Input / output pin 23 ... Plating layer 24 ... Aluminum nitride multilayer circuit board

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location H05K 3/46 H 6921-4E 9355-4M H01L 23/14 C

Claims (1)

[Claims] 1. When manufacturing an aluminum nitride multilayer circuit board having a metallized portion requiring plating, and plating the metallized portion, a plating lead-out wire electrically connected to the metallized portion requiring plating. Is provided so as to reach the end surface of the aluminum nitride multilayer substrate, and by irradiating the end surface of the aluminum nitride multilayer substrate with a laser, an aluminum layer electrically connected to the plating lead-out wiring is formed on the end surface. A method for manufacturing an aluminum nitride multilayer circuit board, comprising: plating the metallized portion using the aluminum layer as a plating electrode to manufacture the aluminum nitride multilayer circuit board.