JPH061669A - Method and device for producing ceramic substrate - Google Patents

Abstract

PURPOSE:To obtain a high-precision dense ceramic substrate with the nonuniformity due to contraction reduced in sintering by moving a substrate which is being horizontally rotated and sintering the substrate in a sintering furnace. CONSTITUTION:The gas atmosphere in a sintering furnace 1 is firstly adjusted to sinter a ceramic substrate 2, and the rotating chains 6 of a rectilinearly moving machines 3 are driven. The substrates 2 are transferred by a conveyor and placed on the setters arranged on turntables 7, the turntables 7 are horizontally rotated and rectilinearly moved in the furnace 1 by a rack and a pinion, and the substrates 2 are continuously sintered. Accordingly, the substrate 2 is uniformly contracted in sintering, and the difference in thermal contraction of the ceramic substrate 2 before and after the furnace 1 is reduced.

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 a ceramic substrate and an apparatus therefor, and more particularly, to a ceramic substrate such as a multilayer circuit (wiring) substrate or an IC substrate, in which a front portion and a rear portion in a firing advancing direction. The present invention relates to a method for manufacturing a ceramic substrate and a device for manufacturing the ceramic substrate, in which the difference in heat shrinkage between the two is reduced and the dimensional accuracy can be continuously manufactured.

[0002]

2. Description of the Related Art In recent years, with the miniaturization and high density of modules, the demand for ceramic multilayer wiring boards has been increasing. Further, the components mounted on the substrate are also becoming smaller and narrower in pitch, and the yield is good, and the precision of the substrate dimension is required to be ± 0.01 mm for mounting.

On the other hand, in order to increase the mounting efficiency, it is required to mount a large number of substrates including as many substrates as possible on one sheet, and the size of the sheet is expanded from the conventional 50 mm square or 75 mm square to 100 mm square. I am doing it. 1
Even with a 00 mm square substrate, the dimensional accuracy of ± 0.1 mm is
This corresponds to ± 0.10%.

By the way, the ceramic multilayer wiring substrate is produced by the green sheet method, but the firing is performed continuously in a belt furnace. That is, the ceramic multilayer wiring board is placed on a belt and fired by moving in a firing furnace in which the gas atmosphere is kept constant to manufacture a ceramic multilayer wiring board.

[0005]

However, in the case of the above-described conventional method for manufacturing a ceramic substrate, deformation due to nonuniformity of shrinkage in each substrate occurs during firing, and the dimensional accuracy is ±
There is a problem that the limit is 0.3 to 0.4%.

The inventor of the present invention has dealt with this problem and has conducted various tests and studies. In the case of the manufacturing method, the temperature difference between the front and rear portions of the ceramic substrate to be fired is different from that of the belt traveling direction. Since the front part of the substrate in the firing progress direction is heated and shrinks first, the shrinkage becomes more uneven than that of the rear part, resulting in a decrease in dimensional accuracy and deformation due to firing. .

The present invention is a method and apparatus created in view of the above points. The object of the present invention is to reduce nonuniformity due to shrinkage during firing of a fired ceramic substrate, and to achieve high precision and high accuracy. It is an object of the present invention to provide a manufacturing method and a device for manufacturing a ceramic substrate having a high density.

[0008]

The method for manufacturing a ceramic substrate of the present invention as a means for solving the above problems is as follows: when a ceramic substrate to be fired is fired in a firing furnace to produce a ceramic substrate, The ceramic substrate to be fired is fired by moving it while horizontally rotating.

Further, the apparatus for manufacturing a ceramic substrate of the present invention comprises a forward moving mechanism for moving the fired ceramic substrate forward in the firing furnace, and a horizontal rotation mechanism for horizontally rotating the fired ceramic substrate. Is provided, and the ceramic substrate to be fired can be horizontally rotated and moved forward in parallel in the firing furnace.

[0010]

According to the method for manufacturing a ceramic substrate of the present invention having the above-described structure, for example, when the ceramic substrate to be fired is moved straight while being horizontally rotated in the firing furnace, the ceramic substrate to be fired at the time of entering the firing furnace is moved. The front and rear points move in an advancing direction while drawing an arc, and the front point of the fired ceramic substrate is x = rcosωt + vty y = rsinωt The back point of the fired ceramic substrate is x = rcos (ωt + π) + vt y = rsin (ωt + π) where ω ... angular velocity of the fired ceramic substrate v ... velocity of the fired ceramic substrate in the straight direction (x direction), and the front and rear points of the fired ceramic substrate are It is evenly baked. Therefore, the moving velocity v in the straight traveling direction and the angular velocity ω of the ceramic substrate to be fired serve to draw a locus of a trochoid and reduce the thermal contraction due to firing.

Further, the apparatus for manufacturing a ceramic substrate of the present invention comprises a forward moving mechanism for moving the fired ceramic substrate forward in the firing furnace, and a horizontal rotation mechanism for horizontally rotating the fired ceramic substrate. Since the ceramic substrate to be fired is provided, the fired ceramic substrate can be moved while being horizontally rotated in the firing furnace, and both operations can be performed smoothly in parallel.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. Here, FIG. 1 to FIG.
FIG. 1 shows an embodiment of the present invention, and FIG.
2 is a vertical sectional view of the firing furnace, FIG. 3 is a plan view of the inside of the firing furnace,
FIG. 4 is an explanatory diagram of a ceramic substrate for explaining a method of measuring the amount of deformation due to thermal contraction after firing, FIG. 5 is a diagram of measuring the amount of deformation of the ceramic substrate by the example method, and FIG. 6 is a ceramic substrate by the comparative example method. FIG. 7 is a locus explanatory view for explaining a locus of the ceramic substrate to be fired in the firing furnace.

The present embodiment is an apparatus for manufacturing a ceramic substrate, and roughly speaking, a linear moving mechanism 3 for linearly moving the ceramic substrate 2 to be fired inside the firing furnace 1 and a ceramic substrate 2 to be fired are horizontally rotated. It is composed of a horizontal rotation mechanism 4.

As the firing furnace 1, a general muffle furnace is used, and it comprises a firing furnace capable of continuously firing at a temperature rising rate of 10 ° C./min and a maximum temperature of 900 ° C. for 20 minutes. The heating method used, the composition of the atmospheric gas, and the exhaust structure are the same as those of the belt baking furnace, and the straight moving mechanism 3 continuously moves the ceramic substrate 2 to be fired.

The linear movement mechanism 3 includes chain guides 5, 5
And the rotary chains 6, 6 and the turntable 7. Chain guides 5 and 5 are firing furnace 1
, Which are installed on the left and right sides of the inside of the rotary chain, and the rotary chains 6 and 6 are provided on the upper part thereof, and a plurality of connecting plates 8 and 8 are connected between the rotary chains 6 and 6 at predetermined intervals. ，
The turntables 7, 7 ... On which the fired ceramic substrate 2 is placed are attached to the central portion of 8 ... so that the fired ceramic substrate 2 can be moved straight in the firing furnace 1.

Further, the horizontal rotation mechanism 4 includes turntables 7 on which the ceramic substrate 2 to be fired is placed, and bearings 9.
And the pinion 10 connected via the
And a rack 11 that meshes with the rack 11. And
The horizontal rotation mechanism 4 is driven by the driving force of the rotation chains 6 and 6 that form the rectilinear movement mechanism 3 to move the rack 11 and the pinion 1 together.
.. is configured to horizontally rotate the turntables 7, 7 ... By converting the linear motion due to the meshing with 0 into a rotary motion.

Next, a method of firing the fired ceramic substrates 2, 2, ... Using the apparatus for producing a fired ceramic substrate of this embodiment will be described. First, after adjusting the gas atmosphere in the firing furnace 1 to the firing conditions for the ceramic substrate 2 to be fired, the rotary chains 6 and 6 of the linear movement mechanism 3 are driven. When the fired ceramic substrates 2, 2, ... Transferred from a conveyor device (not shown) are placed on a setter installed (arranged) on the turntables 7, 7 ,. , The rack 11 and the pinion 10 move horizontally while moving horizontally to move inside the firing furnace 1, during which the fired ceramic substrates 2, 2 ... Can be fired continuously.

Accordingly, since the ceramic substrate 2 to be fired is moved in the firing furnace 1 while being horizontally rotated by the horizontal rotation mechanism 4 inside the firing furnace 1, the shrinkage due to the firing is made uniform. Therefore, the difference in heat shrinkage between the front and rear portions of the ceramic substrate 2 to be fired entering the firing furnace 1 can be reduced.

Here, the straight movement and the horizontal rotation of the ceramic substrate 2 to be fired in the firing furnace 1 move in the firing furnace 1 along a locus of forward movement while horizontally rotating, as shown in FIG. Here, the locus of the horizontal rotation is the rack 11
And the gear configuration of the pinion 10 and turntable 7,7
Although the angular velocity of .. is determined, although not shown, the gear configuration can be changed so that it can be changed.

Next, in order to confirm the effect of this embodiment,
Using the same ceramic substrate 2 to be fired, a method for manufacturing a ceramic substrate of this embodiment (hereinafter referred to as the method of this embodiment)
And a conventional method of producing a ceramic substrate by moving straight in a firing furnace, a ceramic substrate is produced, and the result of comparison by measuring the amount of deformation due to shrinkage after firing is described. .

Here, as the ceramic substrate to be fired, Ca
O-Al ₂ O ₃ -SiO ₂ -B ₂ O ₃ based glass powder: 60 wt% and alumina powder: 40 wt% A mixed powder containing a solvent, a binder and a plasticizer, and kneaded to obtain a slurry. By a doctor blade method to prepare a green sheet having a thickness of 0.3 mm, and after the firing, 2
A through hole 12 of 0.5 mmφ is drilled so as to form a grid pattern of 5 mm pitch, and four holes are formed at 100 ° C. and 50 kg / c.
A laminated body thermocompression bonded under the condition of m ² for 20 seconds was used. Further, the firing conditions are a temperature rising rate of 10 ° C./min and a maximum temperature of 9
It was kept at 00 ° C for 20 minutes.

The method of measuring the amount of deformation due to the heat shrinkage is as shown in FIG. 4, in which the measurement points (B1, B2, B3, 25) of the 25 lattice-shaped holes 12, 12 ... ... B2
5) (Refer to Fig. 4) and virtual normal points after firing considering the shrinkage of the substrate, that is, design points (A1, A2, A3 ... A25)
(See Figure 5 and Figure 6) Distance (in other words, deviation) | A1
-B1 |, | A2-B2 |, ..., | A25-B25 | were measured, and at that time, A13 and B13 at the center of the substrate were set as the same point as the origin.

In the method of this embodiment, the number of revolutions is once /
Three types of baking were performed for 1 minute, 1/3 times, and 1/10 minutes, and a comparison test was performed 5 times for each of the method of this example and the method of the conventional example. Then, the distance (in other words, deviation) | A1-B1 |, | A2-B2 |, ..., | A25-
Table 1 shows the maximum value of B25 | as the amount of deformation. Here, in Table 1, the deformation ratio is 100 × deviation | A _n −B
_n | / distance | origin-design point | a (%) is the maximum value.

[0024]

[Table 1]

As shown in Table 1, in the case of the method of this embodiment, the deformation amount of the comparative example method is 0.236 mm, whereas the deformation amount is 0 when the number of revolutions is once per minute. 0.063
In addition, it was confirmed that the amount of deformation was 0.115, which is 1/2 of that of the conventional method even at the maximum of 1/10 minutes, and the shrinkage change due to firing was small. From this, it was clarified that the method and apparatus of the present example could manufacture a ceramic substrate with improved dimensional accuracy.

It should be noted that the present invention is not limited to the above-described embodiments, but includes configurations that can be modified and implemented within the scope that does not change the gist of the present invention. Incidentally, in the above-mentioned embodiment,
As the ceramic substrate to be fired, the ceramic multilayer wiring substrate has been described, but a ceramic-only substrate that does not rely on the green sheet method may be used.
Needless to say, the present invention can be applied to all low temperature firing substrates of ˜1100 ° C., alumina substrates, aluminum nitride substrates, and other ceramic substrates made of various ceramic materials (eg, mullite). Further, in the above-described embodiments, the firing furnace is described as a muffle furnace. The good thing is right.

Further, in the above-mentioned embodiment, the moving mechanism of the ceramic substrate to be fired in the firing furnace has been described as a straight moving mechanism, but meandering movement (meandering in the horizontal direction, meandering in the vertical direction). Alternatively, it may be a moving mechanism that moves in a circuit (a structure in which the inside of the firing furnace is folded back). Further, the rotation mechanism and the forward movement mechanism may be driven independently of each other. In the present specification, rotation includes rotation (for example, a form in which normal rotation and reverse rotation are repeated).

[0028]

As is apparent from the above description, according to the method for manufacturing a ceramic substrate of the present invention, since the ceramic substrate to be fired is moved while being horizontally rotated in the firing furnace, any ceramic substrate to be fired can be produced. Each point moves in the traveling direction while drawing an arc, and because it is baked uniformly,
This has the effect of reducing heat shrinkage due to firing and improving the dimensional accuracy.

Further, according to the apparatus for manufacturing a ceramic substrate of the present invention, a forward moving mechanism for moving the fired ceramic substrate forward in the firing furnace and a horizontal rotation for horizontally rotating the fired ceramic substrate. By providing the mechanism, it is possible to move the ceramic substrate to be fired while horizontally rotating in the firing furnace.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of the inside of a firing furnace.

FIG. 2 is a vertical sectional view of a firing furnace.

FIG. 3 is a plan view of the inside of a firing furnace.

FIG. 4 is an explanatory diagram of a ceramic substrate for explaining a method of measuring a deformation amount due to thermal contraction after firing.

FIG. 5 is a measurement diagram of the amount of deformation of the ceramic substrate according to the method of the present embodiment.

FIG. 6 is a measurement diagram of a deformation amount of a ceramic substrate according to a comparative example method.

FIG. 7 is a locus explanatory view for explaining a locus of a fired ceramic substrate in a firing furnace.

[Explanation of symbols]

1 ... Baking furnace, 2 ... Baking ceramic substrate, 3 ...
..Straight moving mechanism (forward moving mechanism), 4 ... Horizontal rotating mechanism, 5 ... Chain guide, 6 ... Rotating chain, 7 ... Turntable, 8 ... Connecting plate, 9 ...
・ Bearing, 10 ... Pinion, 11 ... Rack, 12
... Through holes

Claims (2)

[Claims] 1. When manufacturing a ceramic substrate by firing the ceramic substrate to be fired in a firing furnace, the ceramic substrate is fired by moving it while horizontally rotating it. Production method. 2. A forward moving mechanism for moving the fired ceramic substrate forward and a horizontal rotation mechanism for horizontally rotating the fired ceramic substrate are provided in the firing furnace.
An apparatus for producing a ceramic substrate, wherein the ceramic substrate to be fired can be horizontally rotated and moved forward in parallel in the firing furnace.