JP2001241854A - Baking method of thick-film circuit board and transportation belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a baking method of a thick-film circuit board for a high baking capability without raising a manufacturing cost, and to provide a transportation belt used for the baking method. SOLUTION: On a transportation belt 10, plural board support equipment are provided which respectively comprise first and second placement surfaces 18 and 20, different in height from each other. So, boards 16a and 16b different in size from each other are supported, by their end parts, by the first and second placement surfaces 18 and 20, thus so placing on the transportation belt 10 as to overlap, one being above the other, with an interval about d=2.4 (mm). Thus, with no change in the structure of an oven body, the number of boards placed on a unit area of the transportation belt 10 is almost doubled. So, baking efficiency is almost doubled without raising a manufacturing cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a baking method and a conveyor belt for forming a thick film pattern by applying a thick film printing paste to a substrate.

[0002]

2. Description of the Related Art A thick film circuit board is made of, for example, alumina (Al).
₂ O ₃ ), etc., a thick film printing paste such as a conductor paste, a resistor paste, and a protective glass paste is applied in a predetermined pattern using a thick film screen printing method on a ceramic substrate such as ₂ O ₃ ). Is manufactured by performing a baking process at a predetermined temperature defined in (1) and baking and forming a thick film from the thick film printing paste.

[0003]

The above-mentioned sintering process generally uses a continuous sintering furnace provided with a transport belt made of a metal mesh or the like provided in a longitudinally extending furnace inside the longitudinal direction thereof. The process is performed continuously by moving the substrate on which the thick-film printing paste has been applied along the longitudinal direction of the furnace body using the conveyor belt. In such a firing furnace, the substrates are conventionally arranged directly on a metal mesh by being placed directly on a metal mesh, so that the firing capacity is limited by the width of the belt. Therefore, in order to increase the number of sintering treatments per unit time, it is necessary to increase the size of the sintering furnace or increase the number of sintering furnaces.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method of firing a thick film circuit board capable of obtaining a high firing capacity without increasing the manufacturing cost. An object of the present invention is to provide a conveyor belt suitably used for the firing method.

[0005]

First means for solving the problems In order to achieve the object, the gist of the firing method of the first invention is as follows.
Continuous firing by moving a plurality of substrates on which a thick film printing paste is applied in a predetermined pattern along a longitudinal direction by a transport belt provided in the longitudinal furnace inside a longitudinal direction of the furnace. Then, in the method of firing a thick film circuit board to form a thick film pattern on those substrates, (a) placing each of the plurality of substrates on the transport belt so as to overlap with another substrate at a predetermined distance It is in.

[0006]

According to the first aspect of the invention, each of the plurality of substrates is arranged on the transport belt so as to overlap with another substrate. In this case, the number of substrates placed per unit area of the conveyor belt is more than doubled. Therefore,
A high firing treatment capacity can be obtained without increasing the manufacturing cost. At this time, since the distance between the substrates is kept at a certain value or more, fusion with another substrate due to poor removal of the resin component in the paste or the application surface of the thick-film printing paste being in contact with another substrate. No such troubles occur. Note that "to overlap at a predetermined distance" refers to a state in which the front surface or the back surface of the substrate is substantially opposed to each other with a predetermined distance or more, and is vertically oriented in a direction substantially parallel to the surface of the transport belt. It is not limited to completely overlapping ones, but when the relative position is slightly shifted in the horizontal direction, or when it overlaps in the direction substantially perpendicular to or inclined to the surface of the conveyor belt and before and after in the direction substantially along the conveyance direction, etc. As in the case of partially overlapping.

[0007]

In another preferred embodiment of the present invention, the method for firing a thick film circuit board is such that each of the plurality of substrates is vertically stacked on another substrate. By doing so, the height range in which the substrates are arranged can be kept narrower than in the case where the substrates are lined up vertically or inclined with respect to the surface of the transport belt, and a plurality of substrates can be arranged. May be located at a uniform height. Therefore, in a firing furnace for a thick film circuit board in which the height of the inside of the furnace is relatively reduced in accordance with the assumed size of the object to be fired, the size of the substrates that can be arranged in an overlapping manner is the height of the inside of the furnace. The size is not limited, and the occurrence of thermal stress in the substrate due to the temperature distribution in the height direction in the furnace body is prevented from being damaged.

[0008] Preferably, the mutual interval between each of the plurality of substrates and another substrate is 1.6 (mm) or more. In this way, since the mutual interval is set to a sufficiently large value of 1.6 (mm) or more, the resin component in the thick-film printing paste can be gaseous without interruption even on the surface located between the substrates. And discharged from between them. For this reason, it is possible to further suppress the occurrence of defective removal of the resin component and the resulting poor adhesion of the thick film.

[0009] Preferably, the thick film printing paste is a conductor paste or an insulator paste. This makes it difficult for the characteristics of the thick film conductor and the thick film insulator to differ due to the difference in the firing conditions, so that the manufacturing efficiency of the circuit pattern formed on the thick film circuit board is not changed. Can be increased. Incidentally, other components of the circuit pattern of the thick-film circuit board include a thick-film resistor and the like. However, the resistance of the thick-film resistor tends to fluctuate easily due to a slight change in firing conditions. Therefore, when the substrates are stacked one upon another during firing of the thick film resistor, it is necessary to control the firing conditions with high accuracy. There is an advantage that the firing efficiency can be easily increased without particular consideration. More preferably, said thick film printing paste is a thick film conductor paste. Thick film conductors are less likely to cause poor foaming or the like due to poor binder removal than thick film insulators, and thus it is easier to increase firing efficiency while maintaining conventional characteristics.

[0010]

A second aspect of the present invention is a transport belt used for suitably executing the above-described method for firing a thick film circuit board. (A) a plurality of first mounting surfaces provided at a first height position from a predetermined horizontal reference surface and on which an end of the substrate is mounted,
(b) an end portion of another substrate provided at a second height position higher than the first height position and superposed at a predetermined distance above a substrate placed on the first placement surface; And a plurality of second placement surfaces on which the information is placed.

[0011]

According to this structure, the transport belt has a first mounting surface provided at the first height position and a second mounting surface provided at the second height position higher than the first mounting surface. By providing a plurality of mounting surfaces, the substrate is mounted so as to vertically overlap the first mounting surface and the second mounting surface at a predetermined distance from each other. Therefore, the number of substrates placed per unit area of the conveyor belt is more than doubled as compared with the case where the substrates are arranged on one plane while using the same baking furnace as before. Therefore, the firing capacity can be increased without increasing the manufacturing cost. The difference between the height positions of the first mounting surface and the second mounting surface is determined so that the substrates to be mounted thereon are separated from each other by a predetermined distance. There is no problem such as fusion with another substrate caused by contact of the application surface with another substrate.

[0012]

According to another aspect of the second invention, preferably, the transport belt integrally has at least one of the first mounting surface and the second mounting surface, and has the first height. It includes a plurality of substrate supports mounted in a fixed posture at a mounting portion provided at a position lower than the position. With this configuration, the substrates are transferred on the first mounting surface or the second mounting surface provided on each of the plurality of firing jigs so that the plurality of substrates overlap with a predetermined distance. It is placed on a belt.

Preferably, the conveyor belt integrally includes the first mounting surface and the second mounting surface, and a mounting portion provided below the first mounting surface. And a plurality of substrate supports attached in a fixed posture. According to this configuration, since each of the plurality of substrate supports has both the first mounting surface and the second mounting surface, a case where the substrate support having only one of them is used is used. This makes it easier to attach the firing jig to the conveyor belt, change the position, and the like. Moreover, since the number of components attached to the transport belt is reduced, there is an advantage that an increase in heat capacity due to the use of the substrate support is suppressed.

Preferably, the conveyor belt extends upward from the first mounting surface and the second mounting surface, respectively, and has an end at the first mounting surface and the second mounting surface. It includes a first movement suppression surface and a second movement suppression surface which are provided so as to face the end surface of the mounted substrate and suppress the horizontal movement of the substrate. If you do this,
Since the first movement suppressing surface and the second movement suppressing surface extending upward from the first placing surface and the second placing surface, respectively, the end surfaces are provided on the first movement suppressing surface and the second movement suppressing surface. The horizontal movement of the substrate is suppressed by being abutted. Therefore, the “first movement suppression surface and the second movement suppression surface facing the end surface of the substrate” are not limited to those parallel to the end surface of the substrate, and are not limited to the extent that the substrate does not climb over when the end surface abuts. As long as it forms the step, there is also included one that is inclined with respect to the end face.

Preferably, in the conveyor belt, the first height position is different from the second height position by a value obtained by adding 1.6 (mm) to the thickness of the substrate. Is what you do. With this configuration, the interval between the substrates supported by the plurality of first mounting surfaces and the second mounting surface is 1.6 (m).
m) As described above, the resin component in the thick-film printing paste is gasified without interruption even on the surfaces located between the substrates, and is discharged from between them. for that reason,
Insufficient removal of the resin component, and the resulting occurrence of poor adhesion of the thick film, are further suppressed.

Preferably, the first mounting surface and the second mounting surface have different horizontal positions from each other. With this configuration, since a plurality of mounting portions having different horizontal positions are provided, a change in the mounting position of a plurality of types of substrates using a common substrate support may be involved. It is possible to support without.
Therefore, there is an advantage that high firing efficiency can be obtained even when sequentially firing a plurality of types of substrates.

[0017]

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

FIG. 1 shows an example of an embodiment of a baking method according to the present invention, in which a conveyor belt 10 is provided which penetrates a longitudinal furnace body 42 described later in the longitudinal direction thereof.
Is a plan view showing a part of the longitudinal direction. In the figure, a number of substrate supports 14 are attached to one surface of a metal mesh 12 having high flexibility and high heat resistance in a longitudinal direction, that is, a conveying direction of the conveyor belt 10 shown by an arrow F in the figure. It is constituted by.

The above-mentioned substrate supports 14 are attached at regular intervals in the transport direction and the width direction perpendicular thereto, for example. This substrate support 14
Is for supporting a plurality of substrates 16 which are objects to be fired on the conveyor belt 10 as shown by a dashed line in the figure. In the drawing, a set of four substrate supports 14 is used, and each of the plurality of substrates 16 is made of metal by mounting four end portions thereof on the four substrate supports 14 respectively. It is supported above and spaced from the mesh 12. In addition, two types of substrates 16a and 16b having different sizes are placed on the pair of substrate supports 14 so as to be vertically overlapped. The substrate 16 is, for example, a thick film conductor paste 15 containing copper powder or the like as a conductor component on one or both sides of a ceramic substrate made of alumina or the like having a thickness of about 0.8 (mm) as shown in FIG. It is applied with a simple circuit pattern 17. One relatively small substrate 16a has a size of about 100 × 100 (mm),
The other relatively large substrate 16b is processed to a size of about 120 × 120 (mm).

FIG. 3 shows a state in which the substrates 16a and 16b are mounted on the substrate support 14 described above.
4 (a) and 4 (b) are a front view and a right side view showing a state where the substrate support 14 is attached to the metal mesh 12, respectively. Substrate support 1
Reference numeral 4 denotes a belt-shaped heat-resistant metal having a width dimension of about 10 (mm) and a thickness dimension of about 0.5 (mm) made of, for example, heat-resistant steel, and formed by press bending or the like. By being alternately bent to the front side and the back side, the central portion as a whole has the highest mountain shape. Substrate 1
Reference numerals 6a and 16b denote first mounting surfaces 18, which are provided substantially symmetrically at different height positions on the substrate support 14, respectively.
18 and the second mounting surfaces 20, 20.

The first mounting surface 18 provided substantially symmetrically
And between the pair of second mounting surfaces 20, 20 located on the upper side of the second mounting surfaces 20, extend obliquely upward from their inner ends and approach each other at the upper end. Are provided. Each of the pair of inclined surfaces 22 is inclined upward and forms an obtuse angle with the second mounting surface 20, 20 provided horizontally. Also, the inclined surface 22,
Between the first mounting surface 18 and the second mounting surface 20 provided on both sides of the mounting surface 22, there are provided vertical surfaces 24, 24 which are substantially perpendicular to them. The vertical surface 24 and the inclined surface 22 respectively correspond to the first mounting surface 18.
And substrates 16a and 1 placed on second placement surface 20
6b is provided so as to face the end surface 26 of the substrate 1b.
6a and 16b, the end surface 26 is a vertical surface 24, the inclined surface 2
By being abutted against 2, the movement in the horizontal direction, particularly in the width direction perpendicular to the above-described transport direction, is suppressed, and the substrate is positioned at a fixed position on the substrate support 14. In the present embodiment, the vertical surface 24 corresponds to the first movement suppressing surface and the inclined surface 2
Reference numerals 2 respectively correspond to the second movement suppression surfaces.

Further, the pair of first mounting surfaces 18, 18
Vertical portions 28, 28 extending downwardly in a substantially vertical direction with respect to the outer ends of the vertical portions 28, 28, horizontal portions 30 extending from the lower ends of the vertical portions 28, 28 so as to be substantially horizontally separated from each other, 30 and mounting portions 32, 32 extending downward from the outer ends of the horizontal portions 30, 30 in a direction substantially perpendicular to the horizontal portions 30, 30 are sequentially provided. This mounting part 3
2, 32 are provided with through holes 34, 34, respectively, penetrating in the thickness direction. The substrate support 14 has its mounting portions 32, 3
2 is inserted into the mesh of the metal mesh 12, and the mounting pins 36 penetrating the metal mesh 12 in a direction parallel to the surface thereof are pierced through the through holes 34, 34 so that the metal mesh 12 is inserted into the metal mesh 12. Fixed. In addition,
4 (a) and 4 (b), the lower end of the mounting portion 32 is drawn so as to protrude from the back surface of the metal mesh 12, but actually, they are substantially on the same plane, and the mounting portion 32 is Does not stick out.

In this mounted state, the substrate support 14
Is mounted in a stable posture by the pair of horizontal portions 30, 30 being brought into contact with the surface 38 of the metal mesh 12, so that the first mounting portions successively provided on the upper side thereof are provided. The portion 18 and the second mounting portion 20 are kept substantially horizontal and are located at a certain height h1, h2 from the surface 38 of the metal mesh 12, that is, the horizontal reference surface 38. The height from the horizontal reference plane 38 is about h1 = 3 (mm) for the first mounting surface 18 located on the lower side, and about h2 = 6.2 (mm) for the second mounting surface 20 located on the upper side. . Therefore, the height positions of the first mounting surface 18 and the second mounting surface 20 are
The difference is about 3.2 (mm). The thickness dimension of the substrate 16a is, for example,
Since they are about 0.8 (mm),
The distance d between the substrates 16a and 16b placed on the substrate is 2.4 (m
m). First mounting surface 18 and second mounting surface 20
Is different from each other in accordance with the thickness dimension of the substrate 16a to be mounted on the first mounting surface 18 by 2.4 (m).
m) It is set to a value of about or more. In the present embodiment, the height positions where the first mounting surface 18 and the second mounting surface 20 are respectively provided correspond to the first height position and the second height position, respectively.

FIG. 5 is a vertical cross-sectional view schematically showing the vicinity of a debinding portion provided on the side of the entrance of the fired material for explaining the structure of the firing furnace 40 provided with the above-mentioned conveyor belt 10. . In FIG. 5, the conveyor belt 10 passes through a furnace body 42 of a baking furnace 40 whose longitudinal direction coincides with the left-right direction in the figure, and is hung between a pair of rollers 44 provided before and after the longitudinal direction. Has been passed. A drive roller 46 is provided below the furnace body 42, and its rotation is transmitted by tension acting on the conveyor belt 10 based on the pressing force given by the tension rollers 48, 48 arranged on both sides thereof. The transfer belt 10
Are continuously driven to rotate in the transport direction indicated by an arrow F in the figure, for example. As shown in the figure, the substrate support 14 is provided over the entire length of the transport belt 10. Therefore, the outer peripheral surface of the tension roller 48 that presses the transport belt 10 from the front surface side on which the substrate support 14 is provided has a corresponding position in the axial direction so as not to interfere with the substrate support 14. Are provided with a plurality of peripheral grooves (not shown).

A plurality of heaters 50 are attached at appropriate positions on the upper and lower surfaces of the furnace body 42 at appropriate intervals. Therefore, the heaters 50 are driven and controlled in accordance with a preset program, and each of the plurality of divided ranges in the longitudinal direction in the furnace body 42 is heated, so that the type of the substrate 16 and the thick-film printing A firing profile according to the type of paste and the like is realized.

In the furnace body 42, a plurality of gas introduction pipes 52 whose axial directions substantially coincide with the width direction thereof are provided. The gas introduction pipe 52 is made of, for example, heat-resistant steel, and is provided with a plurality of outlets at a plurality of positions in the axial direction on its lower side and diagonally rearward (rear side in the transport direction), and the like. ), For supplying nitrogen gas into the furnace body 42 at a flow rate of, for example, about 15 (l / min). A box-shaped exhaust box 54 having a lower end opened above the conveyor belt 10 is provided behind the gas introduction pipe 52 in the conveying direction. The exhaust box 54 is for exhausting gas from inside the furnace body 42 through an exhaust pipe (not shown). Therefore, the furnace body 42
The nitrogen gas supplied to the inside of the apparatus is relatively large from a heating unit or a cooling unit (not shown) provided on the front side in the transport direction.
Along with the nitrogen gas introduced at a flow rate of about 160 (l / min), for example, about 80 (l / min) and flowing to the debinding section as shown by arrow A in the figure, an arrow Is sucked in as shown by the arrow and discharged out of the furnace body 42 from the exhaust pipe. This nitrogen gas is introduced for the purpose of preventing oxidation of copper which is a conductor component of the thick film conductor paste.

By baking the substrate 16 using the baking furnace 40 as described above, a thick film conductor paste (for example, a copper paste manufactured by DuPont Co., Ltd.) applied to the circuit pattern 17 as shown in FIG. Conductor paste 9153F
5), a printed substrate 16 is sequentially placed on the conveyor belt 10 at the left end in FIG. 5, and a furnace body whose temperature is set in advance to, for example, a maximum temperature of about 900 (° C.) In the inside 42, the nitrogen gas is transported along the longitudinal direction while flowing the nitrogen gas at the above-mentioned flow rate. In this transfer process, in the binder removing portion shown in FIG. 5, the resin component in the thick film conductor paste printed on the substrate 16 is decomposed or gasified and removed, and only the remaining conductor component or the inorganic binder is contained. In this case, only the conductor component and the inorganic binder are melted in the heating section and hardened in the cooling section, so that a thick film is formed.

At this time, since a plurality of substrate supports 14 each having a first mounting surface 18 and a second mounting surface 20 having different heights are provided on the transport belt 10, The substrates 16a and 16b having different sizes from each other are placed on the first mounting surface 18 as shown in FIGS.
Further, since the end portion is supported by the second mounting surface 20, the second mounting surface 20 is mounted on the transport belt 10 so as to overlap with the upper and lower sides by about d = 2.4 (mm). Therefore, the number of substrates placed on the conveyor belt 10 per unit area is almost doubled without changing the structure of the furnace body 42 at all. That is, the sintering efficiency is approximately 2 without increasing the production cost.
Doubled.

Further, as described above, the difference between the respective height positions h1 and h2 of the first mounting surface 18 and the second mounting surface 20 is set to about 3.2 (mm).
Since the mutual distance d between 6a and 16b is sufficiently large, about 2.4 (mm), the nitrogen gas introduced into the furnace body 42 is sufficiently supplied between them. Therefore, the decomposition gas and the like of the resin component in the thick film conductor paste are quickly removed without staying on the surface of the substrate 16a, so that the resin component is gasified and removed from the paste without delay.
Therefore, it is possible to suitably suppress the occurrence of the failure in removing the resin component and the failure in bonding the thick film conductor.

Incidentally, when the substrates 16 are stacked and fired as described above, the entire side surface of the mounted state viewed from the transport direction is as shown in FIG. When the unfired thick film conductor paste is applied to the upper surface of the substrate 16a, the decomposition gas is applied to the substrates 16a and 1b.
6b. It is desirable that these distances d be as large as possible for discharging the gas.
Due to the temperature distribution in the height direction in the inside, the firing state of the substrate 16a and the substrate 16b, for example, the adhesion strength of the thick film conductor and the like may be different. That is, in consideration of the temperature distribution in the furnace body 42, it is desirable that the distance d be as small as possible.
Table 1 below shows the experimental results of examining the relationship between the distance d and the quality of the formed thick film. In addition, "conductor adhesion strength"
The adhesive strength of the thick film conductor when the substrates 16 coated with the thick film conductor paste were stacked and fired was measured by soldering and pulling a copper wire having a diameter of about 0.8 mm. The adhesion state of the generated glass film when the substrate 16 coated with the thick-film insulator paste is stacked and fired is determined by a method in which a copper wire having a diameter of about 0.8 is adhered with a thermosetting resin adhesive and pulled. It has been determined. For the latter glass film, for example, a glass paste QP507 manufactured by DuPont or the like is applied to the substrate on which the thick film conductor is baked in a predetermined pattern, and the maximum temperature is 670.
(° C.) except that the temperature was about (° C.).

[Table 1] Interval d (mm) Adhesive strength of conductor (N / mm ² ) Glass bonded state 5.6 10.5 good 4.0 9.8 good 2.4 11.2 good 1.6 8.5 good 0.8 2.2 poor adhesion

As is apparent from Table 1 above, the substrate 16
When the distance d between a and 16b was about 0.8 (mm), a sufficient adhesion state was not obtained with the thick film conductor and the thick film insulator, and foaming was also observed in the thick film insulator. However,
By setting d = 1.6 (mm) or more, sufficient adhesive strength was obtained, and a good thick film without foaming or the like could be formed.

In this embodiment, the substrates 16a,
Since the baking efficiency is increased by stacking 16b vertically, the baking efficiency is improved by another method, for example, by arranging the substrates on the conveyor belt 10 so that the plane direction is vertical with an appropriate interval therebetween. Compared with the case where the temperature is increased, the temperature distribution in the plane of the substrate 16 does not occur due to the temperature distribution in the height direction in the furnace body 42,
Further, it is not necessary to increase the height in the furnace body 42 in order to stand. Therefore, there is an advantage that only the firing efficiency can be increased without changing the thick film characteristics or modifying the firing furnace 40.

In this embodiment, the transport belt 1
Since the substrate support 14 having both the first mounting surface 18 and the second mounting surface 20 is attached to the substrate 0, the substrates 16a and 16b can be stacked and fired simply by mounting the substrates 16a and 16b thereon. Therefore, there is also an advantage that the process is not particularly complicated because the firing is performed repeatedly.

In this embodiment, the substrate support 1
Since the horizontal positions of the first mounting surface 18 and the second mounting surface 20 provided in 4 are different from each other, by providing a plurality of substrate supports 14 having a single shape on the transport belt 10. The distance between the pair of first mounting surfaces 18 and 18 is different from the distance between the pair of second mounting surfaces 20 and 20. Therefore, two types of substrates 16 having different sizes are used.
There is also an advantage that a and 16b can be fired simultaneously.

Next, another embodiment of the present invention will be described. FIG. 7 is a diagram illustrating substrate supports 56 and 58 according to another embodiment in a state where the substrate 14 is mounted thereon. 7, the substrate support 56 has a pair of mounting surfaces 60, 60 at a height of about h1 = 3 (mm) from a horizontal reference plane (the surface of the metal mesh 12) 38. The substrate support 58 is provided with a pair of mounting surfaces 62, 62 at a height of about h2 = 6.2 (mm) from the horizontal reference plane 38. In addition, a pair of inclined surfaces extending between the mounting surfaces 60, 60 and between the mounting surfaces 62, 62 so as to approach each other diagonally upward from their inner ends, and are connected to each other at the upper end. Surfaces 64, 64 and a pair of inclined surfaces 6
6, 66 are provided. Those inclined surfaces 64, 66
Are inclined upward, and form obtuse angles with the mounting surfaces 60 and 62 provided horizontally.

Accordingly, in the present embodiment, the mounting surfaces 60 and 62 having different heights from each other are provided separately from the substrate support 5.
6, 58, respectively, on which substrates 16a, 16b are respectively mounted. The inclined surfaces 64 and 66 are similar to the inclined surface 22 and the vertical surface 24 of the above-described embodiment, and are respectively provided with the substrates 16 mounted thereon.
a, 16b are provided so as to be substantially opposed to the end faces, and function as a movement suppressing surface for suppressing their movement in the horizontal direction. In the present embodiment, the mounting surfaces 60 and 62 are the first
The inclined surfaces 64 and 66 correspond to a first movement suppression surface and a second movement suppression surface, respectively, on the placement surface and the second placement surface. The positions of the heights h1 and h2 of the mounting surfaces 60 and 62 are determined so that the mutual distance d between the mounted substrates 16a and 16b is, for example, about 2.4 (mm) as in the above-described embodiment. I have.

Even when the above-described substrate supporting member 14 is provided on the transport belt 10, the substrates 16a and 16b are placed on the transport belt 10 in an overlapping manner. There is an advantage that the transfer efficiency of the substrate 16, that is, the firing efficiency can be increased without substantially increasing the manufacturing cost. FIG. 7 schematically shows a cross section viewed from the transport direction similarly to FIG. 6, and when a plurality of substrates 16 are arranged in a width direction perpendicular to the transport direction, FIG. 7, a substrate support 58 is further attached to at least one of the left and right directions in FIG. 7, and the substrate support 58 and the substrate support 5 shown in FIG.
The substrate 16b is placed between the eight. In this case, since the substrate supporting member 58 is provided with only the pair of mounting surfaces 62, 62, the pair of substrate supporting members 56 is disposed between them in the same arrangement as shown in the drawing. , 56 are attached so that the substrate 1 can be positioned at the left and right positions in FIG.
6 can be stacked on top of each other.

In this embodiment, the substrate supports 56, 5
6 and the distance between the mounting surfaces 60, 60 and the substrate supports 58, 5
8 differs from the mutual spacing of the mounting surfaces 62, 62 in FIGS.
Are larger than in the case of the embodiment shown in FIG. Therefore, when it is desired in the process to simultaneously bake the substrates 16a and 16b having a larger difference in size, there is an advantage in using the substrate supports 56 and 58 as in this embodiment in combination.

FIG. 8 is a view for explaining a mounting state of a substrate support constituting a main part of the transport belt 10 according to still another embodiment. In this embodiment, the substrate support 1
4, 56 and 58 are used in combination. Therefore, the spacing between the placement surfaces 18 and 60 supporting the ends of the substrate 16a and the placement surfaces 20 and 6 supporting the ends of the substrate 16b are different.
The magnitude of the difference between the two intervals is an intermediate value between the two embodiments. Thus, the substrate supports 14, 56,
By appropriately using the combination of the substrates 58, it is possible to stack a plurality of types of substrates 16 having different sizes and fire them at the same time.

While the embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be implemented in other embodiments.

For example, in the embodiment, the case where the difference between the first height position h1 and the second height position h2 is set to about 3.2 (mm) has been described. The type of resin component in the printing paste and the size of the substrate 16,
It is appropriately changed according to the flow rate of the nitrogen gas and the like.

In the embodiment, the substrate support 1
The inclined surfaces 22, 64, 66 functioning as the movement suppressing surfaces together with the mounting surfaces 18, 20, 60, 62 are provided on 4, 56, 58.
Although the vertical plane 24 is provided, if the substrate 16 is not easily displaced and falls from the support 14 or the like, it is not always necessary to provide the movement suppressing surface. Further, the movement suppressing surface does not necessarily have to be provided integrally with the substrate support 14 or the like.
4 and the like may be provided separately.

In the embodiment, the pair of mounting surfaces 1
A substrate support 14 with 8, 20 is used, or 2
The two substrates 16a and 16b are configured to be fired by being stacked by using the two substrate supports 56 and 58 in combination, but the support having three or more mounting surfaces Or 3 with different mounting surface heights
By using a combination of three or more supports, three or more substrates 16 can be stacked and fired.

Further, in the embodiment, the substrate 16 is constructed so that the substrate 16 can be overlapped and supported by attaching a separately prepared substrate support 14 or the like to the metal mesh 12. The substrate 16 can be stacked and fired using a transport belt provided with a support portion for the substrate 16 by processing or the like.

In the embodiment, the case where the present invention is applied to the firing of the thick film conductor paste or the thick film insulator paste has been described. However, the present invention is also applicable to the firing of other thick films such as a thick film resistor. The invention applies analogously.

Further, in the embodiment, the substrate support 1 is held in a state where the substrate 16 is separated from the metal mesh 12 upward.
4, the substrate 16 may be placed directly on the metal mesh 12 if the thick-film printing paste applied on the substrate 16 is not fired on both sides simultaneously.
That is, using the substrate support 14 shown in FIG.
It is also possible to sinter three substrates 16 one on top of the other.

Further, in the embodiment, two pairs (4) attached at a certain distance from each other in the horizontal direction are provided.
The substrate 16 is supported by the substrate supports 14 and the like, but as long as the substrate 16 can be stably supported, the number of the substrate supports 14 supporting one substrate 16 is appropriately changed. The substrate 16 may be supported by three or five or more substrate supports 14 or the like. Further, it is also possible to use a substrate support provided with two or more mounting surfaces at appropriate intervals to support the substrate 16 with one substrate support.

In the embodiment, the substrates 16a, 1
6b was placed on the conveyor belt 10 so as to overlap vertically, but the substrate 16 was erected so as to be perpendicular or inclined to the surface of the conveyor belt 10, and moved forward and backward in the conveyance direction or the width direction perpendicular thereto. The present invention is similarly applied to other mounting modes such as a case where the substrates are mounted so as to overlap each other.

In the embodiment, the first mounting surface 18
And the second mounting surface 20 or the mounting surface 60 and the mounting surface 62 are mounted with the substrates 16a and 16b having different sizes from each other. By changing the direction between the direction along the transport direction F and the direction perpendicular thereto, substrates 16 of the same or substantially the same size can be stacked and fired.

Although not specifically exemplified, the present invention can be implemented with various modifications without departing from the scope of the invention.

[Brief description of the drawings]

FIG. 1 is a plan view showing a main part of a transport belt used in a firing method according to one embodiment of the present invention.

FIG. 2 is a perspective view showing the entire thick-film circuit board placed on the conveyor belt of FIG. 1 and fired.

FIG. 3 is a perspective view showing the entire substrate support provided on the transport belt of FIG. 1 with a substrate mounted thereon.

FIGS. 4 (a) and (b) are a front view and a right side view, respectively, illustrating a mounting state of the substrate support of FIG. 3;

FIG. 5 is a cross-sectional view illustrating a configuration of a main part of a firing furnace provided with the transport belt of FIG.

FIG. 6 is a schematic diagram illustrating a support state of a substrate on a transport belt.

FIG. 7 is a schematic diagram illustrating a substrate supporting state according to another embodiment of the present invention.

FIG. 8 is a schematic diagram illustrating a substrate supporting state according to still another embodiment of the present invention.

[Explanation of symbols]

 10: Conveying belt 14: Substrate support 16: Substrate 18: First mounting surface 20: Second mounting surface 22: Inclined surface (second movement suppressing surface) 24: Vertical surface (first movement suppressing surface) 38: Horizontal reference plane 42: Furnace body

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4K050 AA04 BA07 BA17 CD16 CG09 CG28 4K055 AA05 HA02 HA12 5E032 AB01 BA04 BB13 CB01 CC06 5E343 AA24 BB24 BB72 FF11 GG11

Claims (9)

[Claims] 1. A method in which a plurality of substrates on which a thick-film printing paste is applied in a predetermined pattern is moved along a longitudinal direction by a transport belt provided through the longitudinal furnace inside the furnace. A baking method for baking a thick-film circuit board, wherein baking is performed continuously to form a thick-film pattern on those substrates, wherein each of the plurality of substrates is placed on the transport belt so as to overlap with another substrate at a predetermined distance. A method for firing a thick film circuit board, comprising: 2. The method according to claim 1, wherein each of the plurality of substrates is vertically stacked on another substrate. 3. The method according to claim 1, wherein a distance between each of the plurality of substrates and the other substrate is 1.6 (mm) or more. 4. The method according to claim 1, wherein the thick-film printing paste is a conductor paste or an insulator paste. 5. The transport belt used in the method for firing a thick film circuit board according to claim 2, wherein the transport belt is provided at a first height position from a predetermined horizontal reference plane, and an end of the substrate is provided. A plurality of first mounting surfaces to be mounted; and a plurality of first mounting surfaces, which are provided at a second height position higher than the first height position and overlap with a predetermined distance above a substrate mounted on the first mounting surface. And a plurality of second mounting surfaces on which the end portions of the other substrates are mounted. 6. At least one of the first mounting surface and the second mounting surface is integrally provided, and is mounted in a fixed posture at a mounting portion provided at a position lower than the first height position. The transport belt according to claim 5, wherein the transport belt includes a plurality of substrate supports provided. 7. A plurality of the first mounting surface and the second mounting surface integrally provided, and a plurality of mounting portions provided at a fixed position in a mounting portion provided below the first mounting surface. The transport belt according to claim 5, comprising the substrate support of (1). 8. The first mounting surface and the second mounting surface extend upward from the first mounting surface and the second mounting surface, respectively, so as to be directed to the end surfaces of the substrates having the ends mounted on the first mounting surface and the second mounting surface. The first is provided to suppress the horizontal movement of the substrate.
The transport belt according to any one of claims 5 to 7, comprising a movement suppression surface and a second movement suppression surface. 9. The method according to claim 5, wherein the first height position and the second height position are different from each other by at least a value obtained by adding 1.6 (mm) to a thickness dimension of the substrate. Any conveyor belt.