JPS58122798A - Method of forming via hole - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming via holes for connecting required portions of a four-millimeter pattern formed downward on an insulating substrate.

In recent years, electronic circuit wiring boards have become high-density wiring boards as logic elements have become more integrated into LSIs, so it is desired to have thinner wiring conductor patterns and smaller TS product mounting holes, via holes, etc. Conventional methods for producing such high-density wiring boards result in increased costs.

As the density of wiring boards increases, the versatility of each wiring board is lost, and the cost of designing wiring boards by the conventional etching method using a raw material becomes a large burden. Furthermore, with the shortening of the life cycle in the electronic device market, there is an urgent need to shorten the design period, but conventional high-density wiring boards have the drawback of requiring a large amount of time to create original designs. Also,
Conventionally, the process of forming via holes requires plating of through holes, resulting in high costs, and requires waste water treatment, which poses the problem of generating pollution.

As shown in FIG. 1(a), the conventional method for forming via holes is to form through holes at required locations in the four-layered layer 2 formed on the upper and lower surfaces of the insulating substrate l, and then to The upper and lower conductor layers are connected by plating the through hole W- as shown in FIG. Then, as shown in FIG. 1C, a resist 19 is formed on the wiring pattern forming portion and through-hole portion of the conductor layer 2, and after etching as shown in FIG. 2D, the resist is removed. This is a method of constructing a wiring board in which upper and lower wiring conductors are connected through via holes as shown in (.).

Figure 2 is a detailed view of the via hole part, and the threshold between the conductor pattern 21 on the upper surface of the 4e rim 1, the 2nd lead s8 connected to this, and the land part 81 on the lower surface of the 48 track body 1 is the through hole. It is connected by a connecting conductor 41 formed in the middle of the 40-meter pot. In the above-mentioned conventional method, a resist is required to preserve the via hole portion during etching, and therefore a master is required for forming the resist. In addition, the plated yang has the above-mentioned problems such as high cost and harm to society.

The present invention solves the above-mentioned conventional drawbacks and provides a method of forming via holes that does not require plating and therefore essentially does not require original drawings, which reduces construction time/around time and reduces costs. The goal is to make the # construction of high-density wiring boards standard.

The method for forming a via hole according to the present invention is based on a method for forming a via hole (
3) A through hole passing through the upper and lower conductors and the S* board is formed at a position where the electronic circuit wiring conductors formed on the lower surface are mutually connected, and the through hole is made of a conductive paste such as KM paste or Fi steel paste. % imitation is injected and electrically connects the upper and lower conductors using paste.

Next, please refer to one drawing regarding the present invention! I will explain in detail.

FIG. 8 shows a cross-sectional view of a conductive paste injection method in one embodiment of the present invention. That is, as shown in FIG. The nozzle 6 is lowered from above along the arrow A into the upper part of the through hole 4 drilled in the connecting part of the substrate l.
A certain gap Gr (for example, 05
m) and then stop. A conductive paste 6 is applied to the inner hole of the nozzle 6. On the bottom surface of the board l, there is a tray 7.
rises along arrow B and makes a constant gap G with the bottom surface of the board.

Stop at the position. Next, as shown in the same figure (b).

- arrow C to conductive paste 5 such as paste or copper paste;
Apply appropriate pressure in the direction shown in to apply the paste 6 to the nozzle 6.
It is extruded from the tip of the through hole 4 and fills the gap Gr-G*. Therefore, the upper and lower edges of the through hole 4 are covered with conductive paste. This top and bottom lll
The conductive paste in the ruts is in sufficient contact with the vertical wiring conductors of the substrate 1. As shown in FIG. It has a swell of R + height from the bottom of the board and a larger width than the diameter R of the through hole, ensuring the connection between the upper and lower wiring conductors. If the conductive paste 6 requires sintering, it is fired in a furnace.

In the above process, the values that are particularly important to control are the viscosity of the conductive paste, the injection pressure, the gap G between the nozzle and the substrate, given the hole diameter R, the hole depth, and the substrate thickness.
1 is the gap G between the saucer and the substrate. In this example,
At room temperature, for the depth L6 of the substrate hole diameter α4-9, the conductive paste viscosity [800 poise, injection pressure 11/
j, nozzle-j Eikaku Gyat 1ub Kaku e5! A good via hole was agglomerated by using a plate of Yoshikaku Yamatsu 106■.

FIG. 4 is a perspective view showing an example of a W&C suitable for carrying out the present invention. That is, the X-axis moving table 8 and the Y@ moving table 9 are attached to the frame 99, and the frame 99
A nozzle 6 is mounted on the upper arm, and a saucer 7 is mounted on the lower arm. The saucer 7 is a rod 7 that is pivotally supported by the bottle 7a.
The trays 7 are formed at both the upper and lower ends in the figure b, and one of the saucers 7 is attached to the substrate 1.
is facing. Then, when the rod 7b rotates 180@ around Bi/7a, the other saucer 7 faces the board l, and the previous saucer 7? Cleaned by #ip2shift1. The nozzle 6 of this device descends into an arbitrary through hole of the positioned substrate 1 to inject and stop the conductive paste. On the other hand, the saucer 'l moves up and down in the vertical direction G, and moves upward during injection.

After receiving the paste, it moves downward and rotates 180@ in the direction of arrow F, and the other saucer is used for the next injection. These operations are continuously controlled by the field computer. Of course, it is also possible to operate it manually.

FIG. 46 rj is a Wt side view showing an example of a via hole formed by the method of the present invention. Namely.

Conductive paste 6 is injected into the through hole 4 drilled through the upward wiring pattern 21 of the substrate l and the land corridor 8 on the lower surface, and the bank s61 on the upper surface and the puncture [62 on the lower surface] cause the upper surface pattern 21 to and is electrically connected to the downward land portion 8. Through hole diameter R1 height H
(appropriate base for) f1511. As mentioned above, the injection pressure is high and the injection pressure is controlled during injection.

, Figure 6 shows an example of a process for creating a multilayer wiring board using the present invention. In other words, as shown in the figure (&), “
A resist 19 is formed on the conductor layer 2 formed on both the upper and lower surfaces of the substrate 1, and unnecessary portions of the conductor layer 2 are removed by etching as shown in the figure (neck).

The resist is removed to form a wiring conductor pattern 21 shown in FIG. At this stage, a via hole has not yet been formed.Next, conductor paste 6 is injected and fired to form a via hole as shown in the figure (・). According to this method, since the formation of the pie hole 7 is performed after the wiring pattern 21 is formed, there is no need for an etching mask to protect the completed via hole plating as in the conventional method. The formation of the wiring pattern can be done in a more convenient way than using the original drawing.Therefore, it is possible to reduce the cost of the multilayer wiring board and shorten the turnaround time.

FIG. 7 shows an example of an electronic circuit package in which pi-7 holes are formed according to the present invention, in which a wiring conductor pattern 21 formed on an insulating substrate 1 is connected to chimp parts 16 and leads [17 are soldered to 18]. It is connected to the wiring pattern 22 on the back side through a via hole filled with conductive paste 6. Since the diameter of the through hole into which the conductive paste 6 is injected is smaller than the line 1 of the wiring patterns gi and ga, it does not interfere with high-density wiring.

As described above, according to the present invention, a via hole is formed by simply filling a conductive paste into a through hole penetrating the upper and lower distributed conductors. No need for it and no pollution. In addition, the via hole formation of the present invention can be performed after the wiring pattern is formed, so there is no restriction on the method of forming the wiring pattern, and therefore, high-density multilayer wiring boards can be produced at low cost and in a short period of time. This can be achieved in a short turnaround time. It would have great advantages if it were used as a multi-product, a pilot product, etc.

[Brief explanation of drawings]

gt diagram is a sectional view of each step showing an example of a conventional via hole forming method, FIG. 2 is a # side view showing a via hole formed by the above conventional example, and FIG. FIG. 4 is a cross-sectional view showing one paste injection; FIG. 4 is a perspective view showing an example of an apparatus for applying the method of the present invention;
#I5 is a sectional view showing an example of a via hole formed by the method of the present invention, and FIG. 6 is a cross-sectional view of a via hole formed by the method of the present invention.
- A sectional view showing an example of a wiring board manufacturing process; FIG. 7 is a perspective view showing an example of an electronic circuit package in which via holes are formed according to the present invention. In the figure, l: insulating substrate, 2: conductor layer, 8:
...Wiring land part, 4...Through hole, 5...Conductive paste, 6...Nozzle, 7...Saucer, 8,9...
・・Moving table. 19...Resist, 21.22... Wiring conductor pattern. Agent: Patent Attorney Toshimune Sumita Figure 1, Figure 2, Figure 3, Figure 4, Figure 5 [

Claims (2)

[Claims] (1) A through hole penetrating the upper and lower conductors and the insulating substrate is formed in the shape of 1ff at a position where the electronic circuit wiring #114 formed on the upper surface and downward of the insulating substrate is connected to each other.
1L, # A method of forming a via hole by injecting a conductive paste such as silver paste or copper paste into a through hole and electrically connecting upper and lower conductors with the conductive paste to obtain an 'It% value. (2) Special If! F. The method for forming a via hole according to claim 1, characterized in that the four-powder paste injected into the through hole is fired.