JPH08139229A - Semiconductor element mounting wiring board and semiconductor device using it - Google Patents

Abstract

PURPOSE: To ensure a larger wiring pattern space on the surface of a substrate by allowing high-frequency operation by reducing signal noise and cross talk and reducing through holes. CONSTITUTION: A through hole 2 is provided on an aluminum substrate 1, and the aluminum conductor is exposed on the inner plane of the through hole. On the front and rear planes of the substrate 1, including the inner plane of the through hole 2, an oxide film 4 is provided by oxidizing the aluminum. On the oxide film 4 in the through hole 2, through hole wiring 6 is provided, and on the oxide film 4 on the front plane of the substrate 1, a wiring pattern 7 to be connected with the through hole wiring 6 is provided. Thus, the through hole wiring 6 is permitted to have a coaxial structure surrounded by the aluminum conductor through the oxide film 4, and when the aluminum substrate 1 is grounded, shield effects are generated. Since the front and rear planes of the substrate can be grounded using the substrate 1, an exclusive through hole for grounding is not necessitated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor element mounting wiring board that handles high-frequency signals or high-speed digital signals and a semiconductor device using the same, and more particularly to a wiring structure in interlayer connection of a board mounting semiconductor elements. To improve signal noise and crosstalk.

[0002]

2. Description of the Related Art Conventionally, BGA (Ball Grid A) is used.
As shown in FIG. 6, the substrate used for the package type semiconductor device includes a through hole 2 in an insulating substrate 21.
2, the inner surface of the through hole is plated with metal to form a through hole wiring 26.
Is connected to the wiring pattern 27 on the substrate,
Inter-layer connection of substrates is performed.

Then, a semiconductor element is mounted on the surface of the inter-layered substrates, the terminals thereof are connected to the wiring pattern 27 by the gold wires 29, and the ball terminals 8 for external connection are provided at the open ends of the through holes 22 on the back surface of the substrate. Is formed so that the ball terminal 8 and the terminal of the semiconductor element are electrically connected to each other, thereby forming a BGA package type semiconductor device.

By the way, the terminals of the semiconductor element include a signal terminal, a ground terminal, and a power terminal, all of which are connected to a wiring pattern formed on the surface of the substrate.
The signal terminal through hole, ground potential through hole, and power potential through hole lead to the ball terminals on the back surface of the substrate. Therefore, a plurality of signal wiring patterns, ground wiring patterns, and power supply wiring patterns run on the surface of the substrate, and through holes of the number corresponding to the number of these wiring patterns are required.

As before, the clock frequency is 50
In a semiconductor device of a relatively low speed of MHz or less, there is no particular problem in that the through holes are simply formed by metal plating to form the through hole wiring. In addition, separate the ground wiring pattern and power wiring pattern from the signal wiring pattern.
There was no particular problem even if they were concentrated in one place. Therefore, the number of these patterns has been relatively small as compared with the signal pattern. In addition, the number of through holes for ground potential and through holes for power supply potential can be reduced accordingly.
The through holes did not often restrict the wiring space on the substrate surface.

[0006]

However, recently, it has become necessary to operate at a clock frequency of 50 MHz or higher due to the speeding up of semiconductor devices. However, conventional through holes are simply formed by metal plating. The through hole wiring has the following problems in operating the semiconductor device at a high frequency.

(1) The signal waveform is distorted due to the impedance mismatch of the through-hole wiring.

(2) Since the signal through-hole wiring is separated from the ground wiring, the signal flowing through the signal through-hole wiring is easily affected by the electric field and magnetic field, which causes crosstalk noise.

(3) Due to high-speed digital signal switching, current concentrates on a small number of ground terminals and power supply terminals, which causes malfunction.

(4) A large number of grounding terminals and power supply terminals are required for noise suppression, but if many are provided, the number of through holes for guiding these terminals to the back surface of the board increases, and the signal pattern wiring on the board becomes large. Not enough space. If a sufficient space is taken, the size of the semiconductor device becomes large.

An object of the present invention is to eliminate the above-mentioned problems of the prior art by introducing a coaxial structure in the interlayer connection of the substrate on which the semiconductor element is mounted, reduce signal noise and crosstalk, and increase the high frequency. It is an object of the present invention to provide a wiring board for a semiconductor element that can be operated in the above-mentioned manner and a semiconductor device using the same.

It is another object of the present invention to provide a wiring board for a semiconductor element and a semiconductor device using the same, which can secure a larger wiring pattern space on the surface of the board by reducing through holes.

[0013]

In the wiring board for mounting a semiconductor element of the first invention, a through hole is provided in a substrate of a metal conductor to expose the metal conductor on the inner surface of the through hole, and the inner surface of the through hole is included. An insulating layer is provided on the front and back surfaces of the substrate, a through hole wiring is provided on the insulating layer in the through hole, and a wiring pattern connected to the through hole wiring is provided on the insulating layer on the surface of the substrate. By providing the through hole wiring, the through hole wiring is surrounded by the metal conductor to form a coaxial structure.

The wiring board for mounting a semiconductor element of the second invention uses a substrate containing aluminum as a main component as a substrate of the metal conductor, and forms the insulating layer with an oxide film on the surface of the substrate.

In the wiring board for mounting a semiconductor element of the third invention, a through hole is provided in an insulating board, and metal conductor layers are provided on the front and back surfaces of the board including the inner surface of the through hole. An insulating layer is provided on the layer, a through hole wiring is provided on the insulating layer in the through hole, and a wiring pattern connected to the through hole wiring is provided on the insulating layer on the surface of the substrate. Thus, the through-hole wiring has a coaxial wiring structure surrounded by the metal conductor layer via the insulating layer.

In the wiring board for mounting a semiconductor element of the fourth invention, the metal conductor layer of the third invention is formed of aluminum,
The above-mentioned insulating layer is formed by an oxide film on the surface of the aluminum.

A wiring board for mounting a semiconductor device according to a fifth aspect of the present invention is the wiring board according to any one of the first to fourth aspects of the invention, for connecting the metal conductor or the metal conductor layer to a ground potential or a power supply potential. A part of the insulating layer on the front and back surfaces is removed to expose the metal conductor or the metal conductor layer.

The semiconductor element mounting wiring board of the sixth invention has a semiconductor element mounted on the surface of the semiconductor element mounting wiring board of the fifth invention, and the signal terminals of the semiconductor element and the wiring pattern are electrically connected. And electrically connecting the ground terminal or the power supply terminal of the semiconductor element to the metal conductor or the metal conductor layer exposed on the surface of the semiconductor element mounting wiring board, and the semiconductor element mounting wiring. A ball terminal that is electrically connected to the signal terminal through the through-hole wiring is provided in the opening of the through-hole on the back surface of the substrate, and the metal conductor or the metal conductor layer exposed on the same back surface is connected to the ground terminal of the semiconductor element or A ball terminal is provided which is electrically connected to the power supply terminal.

[0019]

When the through-hole wiring is surrounded by the metal conductor so as to have the coaxial structure as in the first invention, the characteristic impedance is matched and the signal is not distorted. In particular, if the metal conductor is grounded, the influence of electric field and magnetic field can be suppressed, and the generation of crosstalk noise can be effectively prevented.

When the metal conductor is aluminum and the aluminum oxide film is used as the insulating layer as in the second aspect of the invention, a uniform coaxial structure can be formed, so that the characteristics are improved.

Even when the through hole wiring is surrounded by the metal conductor layer as in the third aspect of the invention, the characteristic impedance is matched and the signal is not distorted. Further, if the metal conductor layer is grounded, the influence of the electric field and the magnetic field can be suppressed, and the generation of crosstalk noise can be effectively prevented.

When an aluminum oxide film is used for the insulating layer as in the fourth aspect of the invention, a uniform coaxial structure can be formed, so that the characteristics are improved.

When the metal conductor or the metal conductor layer is connected to the ground potential or the power source potential as in the fifth invention, the ground potential of the front and back surfaces is connected via the metal conductor or the metal conductor layer forming the coaxial structure of the through hole or Since the power supply potential can be conducted, it is not necessary to separately prepare a through hole for guiding the ground potential or the power supply potential from the substrate front surface to the substrate back surface.

As in the sixth invention, when the semiconductor element is mounted on the surface of the wiring board for mounting the semiconductor element of the fifth invention and the ground terminal or the power supply terminal of the semiconductor element is connected to the metal conductor or the metal conductor layer. Since the ground potential or the power supply potential can be guided to the back surface of the substrate through the metal conductor or the metal conductor layer forming the coaxial structure of the through hole, the through hole for the ground potential or the power supply potential is not necessary, and the space therefor is not necessary. Since it is not necessary, the density of the wiring pattern formed on the substrate surface can be increased.

[0025]

EXAMPLES Examples of a semiconductor element mounting wiring board of the present invention and a semiconductor device using the same will be described below.

(First Embodiment) FIG. 1 shows a first embodiment in which a metal conductor is used for the substrate. An aluminum substrate 1 having a thickness of 1.5 mm and a size of 32 mm is used as a wiring board for mounting semiconductor elements. First, a through hole 2 having a diameter of 1.0 mm is provided at the position of the aluminum substrate where the through hole wiring is provided, and the aluminum conductor is exposed on the inner surface of the through hole (FIG. 1 (a)). Next, an epoxy masking paint 3 is applied to the entire surface of the substrate 1 by 20 μm.
The masking paint 3 is left on the grounding portion on the back surface which is applied to the external ground potential by coating, exposing and developing, and the grounding portion on the surface which is connected to the ground terminal of the semiconductor element (see FIG. 1).
(B)).

Next, an alumite treatment with sulfuric acid is applied,
An oxide film 4 of alumina (Al ₂ O ₃ ) which is an insulating layer is formed on a portion other than the masked portion (FIG. 1).
(C)). At this time, the electric field bath is 10 to 20% H ₂ SO.
₄ , the current density is D. C. 60 to 200 (A / m ² ), voltage is 10 to 25 V, temperature is 15 to 25 ° C., time is 30 to 60
The oxide film 4 having a film thickness of 20 μm can be formed in a minute. After the oxide film 4 is formed, the remaining masking paint 3 is removed to expose the back-side grounding point to be the external ground potential and the front-side grounding point connected to the ground terminal of the semiconductor element (FIG. 1 (d )).

Next, copper is vapor-deposited on the entire substrate including the through holes 2 to form a Cu coating 5 having a thickness of 2 to 3 μm (see FIG. 1).
(E)). Then, masking paint is applied again to 20 μm, exposed and developed, and the Cu film 5 other than the portions to be left as the through hole wiring 6 and the wiring pattern 7 is removed by etching to connect the through hole wiring 6 and this. The wiring pattern 7 is formed (FIG. 1F). The through hole wiring 6 formed in the through hole 2 has a coaxial structure surrounded by the aluminum conductor of the substrate 1 with the oxide film 4 interposed therebetween. Reference numeral 6a is a through-hole electrode, which is a ring-shaped wiring electrode formed at the opening edge of the through-hole when forming the through-hole wiring.

Then, by removing the mask,
The semiconductor element mounting wiring board of this embodiment is completed.

Subsequently, in order to manufacture a BGA package type semiconductor element using this semiconductor element mounting wiring board, the semiconductor element 10 is die-bonded onto the semiconductor element mounting wiring board as shown in FIG. Element 10
Wiring pattern 7 formed on the terminals and the surface of the aluminum substrate 1
And are wire-bonded using the Au wire 9.

The semiconductor element 10 is grounded as shown in FIG.
As shown in (g), the wire 9 is bonded to the grounded portion on the surface of the substrate that has not been anodized. Also, solder is printed on the open end of the through hole 2 on the back surface of the substrate 1 and the back surface grounding portion that has not been anodized,
This is heated to form ball terminals 8a for signal terminals and ball terminals 8b for ground terminals (FIG. 1).
(G)).

Thus, the semiconductor device as shown in FIG. 2 is completed.

When the through-hole wiring 6 formed in the through-hole 2 has a coaxial structure surrounded by a metal conductor made of a substrate aluminum conductor as in this embodiment, the substrate 1 is grounded and the substrate aluminum conductor is grounded. Since the impedance of the through-hole wiring 6 can be obtained, the signal wave is not distorted even when the semiconductor device is operated at a high frequency of 50 MHz or higher. Further, since the through-hole wiring is shielded to the ground potential, the signal flowing through the through-hole wiring is less likely to be affected by the electric field and the magnetic field, and the crosstalk noise is effectively prevented.

Further, an aluminum substrate is used as the substrate, and the ground terminal of the semiconductor element is connected to the surface grounded portion of the substrate,
Since the ball terminals formed at the grounded portion on the back surface are set to the external ground potential and the ground terminals on the front and back surfaces of the substrate are conducted through the substrate, it is not necessary to provide a through hole dedicated to the ground potential. . Therefore, even if a large number of ground terminals are formed to prevent noise, the number of through holes does not have to be increased. Also, since a large number of ground ball terminals can be provided on the back side of the board to spread the current, it is possible that the current may concentrate on a specific ground ball terminal and cause malfunction even when switching with a high-speed digital signal. There is no.

Further, as shown in FIG. 3 (a), ball terminals 8a for signal terminals are arranged in a grid pattern on the back surface of the substrate 1, and a center surrounded by four adjacent ball terminals 8a. If the ball terminal 8b for the ground terminal is arranged at the position, as shown in FIG. 3 (b), the ball terminal 8 for the ground terminal 8 is formed.
Since the wiring pattern space can be secured at the corresponding position on the substrate surface of b, the wiring pattern 7 can be formed at a higher density without increasing the size of the semiconductor device.

(Second Embodiment) FIG. 4 shows a second embodiment in which an insulator is used for the substrate. A glass / epoxy substrate 11 having a thickness of 1.5 mm and a size of 48 mm is used as a wiring substrate for mounting semiconductor elements. First, the through hole 2 with a diameter of 1.0 mm is provided at the substrate position where the through hole wiring is provided (see FIG. 4).
(A)). Aluminum is vapor-deposited on the entire surface of the substrate including the through holes 2 to form an aluminum film 12 having a thickness of 5 μm (FIG. 4B).

Next, an epoxy-based masking paint 3 is applied to the entire surface of the substrate 1 to a thickness of 20 μm, and exposed to light and developed at a backside grounding point connected to an external ground potential and a frontside grounding point connected to a semiconductor element ground terminal. The masking paint 3 is left (FIG. 4 (c)).

Next, an alumite treatment with sulfuric acid is applied,
Alumina (Al ₂ O ₃ ) other than the masked part
Oxide film 4 is formed, and then the remaining masking paint 3 is removed (FIG. 4 (d)). At this time, the electric field bath was 10 to 20% H ₂ SO ₄ , and the current density was D.I. C. 60
~ 200 (A / m ² ), voltage is 10-25V, temperature 1
Oxide film 4 with a thickness of 10 μm at 5 to 25 ° C in 30 minutes
Can be formed.

Next, the mask 13 made of a metal plate covers the portions other than the portions where the Al through-hole wiring 16 is not formed and the portions to be left as the ground connection portions (FIG. 4E). After that, aluminum is vapor-deposited to form an aluminum film having a film thickness of 3 to 5 μm, a masking paint of 20 μm is again applied on the aluminum film, and exposure and development are performed to leave the Al through-hole wiring 16 and the Al wiring pattern 7. The aluminum film other than the above is removed by etching to form the Al through-hole wiring 16 and the Al wiring pattern 17 connected thereto (FIG. 4 (f)). Of these, the Al through-hole wiring 16 formed in the through-hole 2 has a coaxial structure surrounded by the aluminum film 12 via the oxide film 4.

After removing the metal plate mask 13, as shown in FIG. 5, a multilayer wiring board 15 having a plurality of semiconductor elements 14, 14 mounted thereon is formed with an aluminum wiring pattern 7 formed on the surface of the glass / epoxy board 1 by TAB 18. A
Connected by u-Sn junction. After that, solder is printed on the open end of the through hole 2 on the back surface of the substrate and the back surface grounding position not subjected to the alumite treatment, and the ball terminal 8 is heated.
a and 8b are formed (FIG. 4 (g)).

As described above, in the second embodiment, the aluminum film is provided on the insulating substrate having the through holes, and the through hole wiring has a coaxial structure surrounded by the aluminum film, and is formed between the aluminum film and the through hole wiring. The insulating layer is formed by oxidizing the surface of aluminum, and the aluminum film surrounding the through-hole wiring is connected to the ground potential or the power supply potential. Therefore, except that the substrate is not a metal conductor but an insulating substrate, the first
Since the configuration is the same as that of the embodiment, the same effect as that of the first embodiment is obtained. In addition, since the substrate of the second embodiment is an insulating substrate, it is slightly inferior to the first embodiment in that the number of aluminum film processes is increased and the heat dissipation is lowered, but the printed board to be mounted and the coefficient of thermal expansion are reduced. Are substantially the same as each other, which is superior to the first embodiment in that extreme stress is not applied to the solder balls.

(Other Embodiments) In each of the above embodiments, the aluminum conductor or aluminum film surrounding the through-hole wiring is connected to the ground potential, but it may be connected to the power supply potential. Then, the through hole for the power supply potential can be omitted.

[0043]

According to the first aspect of the present invention, since the substrate is made of a metal conductor and the through-hole wiring has a coaxial structure surrounded by the metal conductor so that impedance matching can be achieved, it operates at a high frequency. Even if it is done, a signal waveform with little distortion can be transmitted.

According to the second aspect of the invention, by using an aluminum oxide film for the insulating layer, a uniform coaxial structure can be obtained, so that the characteristics are further improved.

According to the third aspect of the present invention, since the metal conductor layer is formed on the insulating substrate and the through-hole wiring is formed in the coaxial structure surrounded by the metal conductor layer to achieve impedance matching, it is possible to achieve high frequency. A signal waveform with little distortion can be transmitted even when operated.

According to the invention described in claim 4, since the uniform coaxial structure can be obtained by using the aluminum oxide film for the insulating layer, the characteristics are further improved.

According to the invention of claim 5, a part of the insulating layer on the front and back surfaces of the substrate is removed to expose the metal conductor or the metal conductor layer, so that a dedicated through hole is not provided. However, the metal conductor layer can be connected to the ground potential or the power supply potential.

According to the sixth aspect of the invention, since the ground terminals or the power source terminals on the front and back surfaces are made conductive by using the metal conductor or the metal conductor layer forming the coaxial structure, the ground potential or the power source potential is used. Through holes can be reduced, and more wiring space on the substrate surface can be secured.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram of a substrate and a semiconductor device for explaining a first embodiment of a semiconductor element mounting wiring substrate of the present invention and a semiconductor device using the same.

FIG. 2 is an overall perspective view of the semiconductor device according to the first embodiment.

FIG. 3 is an explanatory view of a main part of the semiconductor device according to the first embodiment, in which (a) is a rear view of a substrate provided with ball terminals;
(B) is a surface view of a substrate on which a wiring pattern is formed.

FIG. 4 is a manufacturing process diagram of a main part of a substrate and a semiconductor device for explaining a second embodiment.

FIG. 5 is an overall perspective view of a semiconductor device according to a second embodiment.

FIG. 6 is a cross-sectional view of a main part of a conventional semiconductor device.

[Explanation of symbols]

 1 Aluminum substrate 2 Through hole 3 Masking paint 4 Oxide film 5 Cu film 6 Through hole wiring 7 Wiring pattern 8a Signal terminal ball terminal 8b Ground terminal ball terminal 9 Au wire

Claims (6)

[Claims] 1. A through hole is provided in a substrate of a metal conductor to expose the metal conductor on the inner surface of the through hole, and insulating layers are provided on the front and back surfaces of the substrate including the inner surface of the through hole. By providing through-hole wiring on the insulating layer and by providing a wiring pattern connected to the through-hole wiring on the insulating layer on the surface of the substrate, the through-hole wiring is connected to the metal through the insulating layer. A wiring board for mounting semiconductor elements that has a coaxial structure surrounded by conductors. 2. The wiring board for mounting a semiconductor element according to claim 1, wherein a substrate containing aluminum as a main component is used as the substrate of the metal conductor, and the insulating layer is formed by an oxide film on the surface of the substrate. 3. A through hole is provided in an insulating substrate, a metal conductor layer is provided on the front and back surfaces of the substrate including the inner surface of the through hole, an insulating layer is provided on the metal conductor layer, and the through hole is provided. By providing a through-hole wiring on the insulating layer inside, and by providing a wiring pattern connected to the through-hole wiring on the insulating layer on the surface of the substrate, the through-hole wiring through the insulating layer A wiring board for mounting a semiconductor element, which has a coaxial wiring structure surrounded by the metal conductor layer. 4. The metal conductor layer is formed of aluminum,
The wiring board for mounting a semiconductor element according to claim 3, wherein the insulating layer is formed of an oxide film on the surface of the aluminum. 5. In order to connect the metal conductor or the metal conductor layer to a ground potential or a power supply potential, a part of the insulating layer on the front and back surfaces of the substrate is removed to form the metal conductor or the metal conductor layer. The wiring board for mounting a semiconductor element according to claim 1, which is exposed. 6. A semiconductor element is mounted on the surface of the wiring board for mounting a semiconductor element according to claim 5, and a signal terminal of the semiconductor element and the wiring pattern are electrically connected to each other, and
A ground hole or a power supply terminal of the semiconductor element is electrically connected to the metal conductor or the metal conductor layer exposed on the surface of the semiconductor element mounting wiring board, and a through hole on the back surface of the semiconductor element mounting wiring board. A ball terminal that is electrically connected to the signal terminal through the wiring pattern is provided in the opening, and a ball terminal that is electrically connected to the ground terminal or the power supply terminal of the semiconductor element on the metal conductor or the metal conductor layer exposed on the same back surface. Semiconductor device provided with.