JP2004172214A - Manufacturing method of electronic component by using solder ball - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely fix a solder ball to a smooth face of an insulating substrate 1 in a manufacturing method of an electronic component by using the solder ball 3. <P>SOLUTION: A relative position relation in a face direction of the insulating substrate 1 between the insulating substrate 1 and a substrate fixing jig 2 is made constant. The substrate fixing jig 2 has: a first process for holding the solder ball 3 in a position confronted with a land 6 when the position relation is made constant, and for giving conductor paste 4 on the land 6; a second process for making the substrate fixing jig 2 hold the solder ball 3; a third process for installing the insulating substrate 1 passing through the first process to the substrate fixing jig 2 whose position relation with the insulating substrate 1 is made constant, so that conductive paste 4 is brought into contact with the solder ball 3; a fourth process for heating the insulating substrate 1 and the substrate fixing jig 2 without degenerating conductive paste 4 and without melting the solder ball 3 while an installed state is maintained; and a fifth process for cooling them thereafter. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing an electronic component using a solder ball.
[0002]
[Prior art]
The insulating substrate surface constituting the electronic component is substantially smooth, has an electrode land at a predetermined position on the insulating substrate surface, and a solder ball is fixed on the land. U.S. Pat. No. 6,326,677 discloses that disclosure. This publication proposes a configuration using solder balls for terminals of a so-called chip network resistor.
[0003]
[Problems to be solved by the invention]
One of the difficulties in realizing the above configuration is a means for fixing a solder ball at a position to be a terminal. The reason is that the solder balls easily roll on the insulating substrate surface which is a smooth surface. Also, as shown in FIG. 4, a conductive paste 54 such as a solder paste is provided on the insulating substrate 51, and the solder balls 53 are temporarily fixed on the surface of the insulating substrate 51 on the solder paste, and then the conductive paste 54 is cured by heating. By doing so, means for fixing the insulating substrate 51 and the solder balls 53 is also conceivable. However, in this case, the scattering force of the volatile component of the conductive paste 54 or the deformation due to the modification of the conductive paste 54 may move the solder balls 53, and the adjacent solder balls 53 may be stuck.
[0004]
Therefore, an object to be solved by the present invention is to securely fix a solder ball to a smooth surface of an insulating substrate.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the surface of an insulating substrate constituting an electronic component is substantially smooth, and has an electrode land at a predetermined position on the surface of the insulating substrate, and a solder ball is fixed on the land. In the method for manufacturing an electronic component using the solder balls 3 of the present invention, the insulating substrate 1 and / or the substrate fixing jig 2 are arranged so that the insulating substrate 1 and the substrate fixing jig are in a direction along the insulating substrate 1 surface. The substrate fixing jig 2 has means for holding the solder ball 3 at a position facing the land 6 when the fixed positional relationship is established. After passing through a first step of disposing a conductive paste 4 on the land 6, a second step of holding the required amount of solder balls 3 in the substrate fixing jig 2, and a second step, the insulating step is performed. Substrate with fixed positional relationship with substrate 1 A third step of mounting the insulating substrate 1 having undergone the first step on the fixed jig 2 so that the conductive paste 4 and the solder balls 3 are in contact with each other, and the insulating substrate 1 and the substrate fixing jig having undergone the third step. 2 is a heating step in which the conductive paste 4 is denatured and the solder balls 3 are not substantially melted while the mounting state is maintained, and the conductive paste 4 denatured after the fourth step is stable. And a fifth step of forming
[0006]
The expression “substantially smooth” refers to the case where an element or the like is arranged on the large-sized insulating substrate 1 and then divided into individual electronic components along the slit formed on the surface of the insulating substrate 1. This is because the presence of grooves or other protrusions formed on the surface of the insulating substrate 1 irrelevant to the fixation of the solder balls 3 is regarded as “unsmooth” and the present invention is not interpreted narrowly.
[0007]
The above-mentioned “means for making the relative position between the insulating substrate 1 and the substrate fixing jig 2 constant in the direction along the surface of the insulating substrate 1 and / or the substrate fixing jig 2” is, for example, as shown in FIG. The fitting of the insulating substrate 1 to the opening of the substrate fixing jig 2 as shown in FIG. In the example shown in FIG. 1, since the inner wall of the side surface of the container having the through hole 5 but having the bottom has substantially the same shape as the outer end of the insulating substrate 1, the insulating member is insulated as shown in FIG. When the substrate 1 is inserted into the substrate fixing jig 2, the relative positional relationship between the insulating substrate 1 and the substrate fixing jig 2 in the direction along the surface of the insulating substrate 1 can be kept constant.
[0008]
The “means for holding the solder ball 3 at a position facing the land 6 when the fixed positional relationship is provided” of the substrate fixing jig 2 is, for example, a land to the insulating substrate 1 in the fixed positional relationship. 6 and the conductive paste 4 are designed such that the positions where the solder balls 3 are held in the substrate fixing jig 2 are matched with the positions where the solder balls 3 are held in advance.
[0009]
The “means for holding the solder balls 3” included in the substrate fixing jig 2 can hold the solder balls 3 on the substrate fixing jigs 2 at a plurality of positions where the solder balls 3 are to be held, for example, as shown in FIG. 1. It has a concave portion or through hole 5 of a size. As a result of the presence of the recess or through-hole 5, the easily rolled solder ball 3 rolls, and as a result, partially falls into the recess or through-hole 5 and is retained thereafter. In this holding state, a part of the solder ball 3 needs to be exposed above the concave portion or the through hole 5. The reason is that the third step of making contact with the conductive paste 4 arranged on the land 6 on the surface of the insulating substrate 1 is to be halted thereafter. Further, even when a concave portion is employed as a means for holding the solder ball 3, it is preferable that the concave portion has a hole for sucking the solder ball 3, and the suction hole communicates with the outside of the substrate fixing jig 2. . In order to increase the work efficiency of holding the solder balls 3 in the recesses or through holes 5, the case where air is sucked from the outside of the substrate fixing jig 2 is considered.
[0010]
In the “second step”, “the board fixing jig 2 holds the necessary amount of solder balls 3”, for example, before the second step, more solder balls 3 are supplied to the board fixing jig 2 than necessary. It is preferable to have a mechanism for collecting the surplus solder balls 3 from the substrate fixing jig 2 after the second step and before the third step. Specifically, after supplying more solder balls 3 than necessary to the bottom surface of the container of the substrate fixing jig 2 in FIG. 1, the solder ball 3 is rolled in the container by tilting or vibrating the substrate fixing jig 2. Then, the solder balls 3 are gradually held in the openings of the through holes 5. When the solder balls 3 are held in all the openings of the through holes 5, the solder balls 3 are provided on the side surfaces of the board fixing jig 2 not shown in FIG. Out of the board fixing jig 2 and collect it.
[0011]
As the “conductive paste” in the third step, for example, a solder paste or a conductive adhesive can be suitably used. When the solder paste is used, the “denaturation” of the solder paste in the fourth step is “melting”, and the “stabilization” of the solder paste in the fifth step is “solidification”. When the thermosetting conductive adhesive is used, the “modification” of the thermosetting conductive adhesive in the fourth step is “the progress of curing”, and the “deformation” of the solder paste in the fifth step is "Stabilization" is "stopping the progress of curing" by, for example, cooling. When a material other than a solder paste or a thermosetting conductive adhesive is used as the “conductive paste”, the terms “denaturation” and “stabilization” can be interpreted accordingly. The means for disposing the conductive paste 4 on the land 6 in the "first step" is preferably screen printing, for example, in view of mass productivity.
[0012]
According to the method for manufacturing an electronic component using the solder ball 3 of the present invention described above, the solder ball can be securely fixed even on the smooth surface of the insulating substrate 1, and the problem to be solved by the present invention is as follows. Clearly, it can be solved. In addition, in the unit substrate fixing jig 2, the height of the solder balls 3 protruding from the insulating substrate 1 can be made uniform by unifying the shape of the concave portion or the through hole 5. This is because the board fixing jig 2 can be a member for adjusting the height of the solder ball 3.
[0013]
It is extremely difficult to make the solder balls 3 uniform in height by the method of fixing the solder balls 53 described with reference to FIG. This is because it is impossible to predict how the solder balls 53 solidify while contacting the conductive paste 54. If a single electronic component has four or more solder balls 3 as terminals, if one of the solder balls 3 is smaller than the other solder balls 3 and has a lower projecting height, the electronic component is placed on the circuit board. When the surface is mounted, the small solder balls 3 may not be able to be reliably electrically connected to the circuit board. Therefore, it is very important to make the height of the solder ball 3 uniform in the unit electronic component.
[0014]
In this regard, in the present invention, the heights of the solder balls 3 can be made uniform among the unit electronic components by performing the third to fifth steps particularly in a positional relationship where the insulating substrate 1 is placed on the substrate fixing jig 2. Be certain. The reason is described below. In the third step, the insulating substrate 1 is mounted on the substrate fixing jig 2 so that the conductive paste 4 and the solder balls 3 are in contact with each other, and this mounting state is maintained until the fifth final step. Therefore, even if only one small solder ball 3 is sunk, the small solder ball 3 is not buried deep in the conductive paste 4 and the other solder ball 3 held by the substrate fixing jig 2 is not buried. This is to end the final process while maintaining the same holding state.
[0015]
The unevenness of the height of the solder ball 3 in the unit electronic component tends to occur particularly when the land 6 is formed in a thick film by a screen printing method or the like. This is because it is difficult to make the film thickness uniform. However, in particular, for the above reason, in the present invention, even when the land 6 is formed as a thick film, the height of the solder ball 3 in the unit electronic component is unlikely to be uneven. Therefore, the adoption of the present invention is advantageous for an electronic component having a thick land 6.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
A large insulating substrate 1 made of alumina ceramic is prepared. On one surface of the large-sized insulating substrate 1 are provided vertical and horizontal dividing grooves, and the smallest unit of the insulating substrate 1 after the division constitutes a unit electronic component. The process of forming elements and the like on the surface of the large insulating substrate 1 having the groove will be described below with reference to the drawings. In the drawings, the minimum unit of the insulating substrate 1 is shown.
[0017]
First, an Ag-Pd-based conductive paste is screen-printed on the insulating substrate 1 shown in FIG. 2 and then fired to obtain the electrode 12 and land 6 and the common electrode 11 and land 6 for the device (FIG. )). Next, a metal glaze-based resistor paste mainly composed of ruthenium oxide and glass frit is screen-printed so as to be in contact with both the common electrode 11 and the electrode 12, and then fired to obtain the resistor 7 (FIG. 2B). )). Next, a glass paste is screen-printed so as to cover the resistor, and then fired to obtain a glass film 8 (FIG. 2C). Next, a step of forming a trimming groove 9 in the resistor 7 by laser irradiation and adjusting the resistance in order to make the resistance of the resistor composed of the electrode 12, the common electrode 11 and the resistor 7 a desired value. (FIG. 2D). At this time, the film of the glass 8 acts to minimize damage to the entire resistor 7. Next, the overcoat 10 is screen-printed with an epoxy resin-based paste to protect the entire resistance element, and then the epoxy resin paste is cured by heating (FIG. 2E). When disposing the overcoat 10, the necessary lands 6 of the electrode 12 and the common electrode 11 are exposed (FIG. 2E). Next, a solder paste as the conductive paste 4 is disposed on the land 6 by screen printing as shown in FIG. 2F (first step).
[0018]
As shown in FIG. 1 (a), the insulating substrate 1 having the resistance element obtained through the above process is transferred to the opening of the substrate fixing jig 2 made of alumina ceramic having the solder balls 3 held on the bottom surface of the container. Fit. At this time, the position of the land 6 of the insulating substrate 1 and the position of the held solder ball are opposed to each other in the fitted state. As a result, the solder paste and the solder balls 3 come into contact as shown in the cross-sectional view of FIG. 1B (third step).
[0019]
The holding method (second step) is performed according to the following procedure. First, an excessive amount of solder balls 3 is supplied from the opening of the board fixing jig 2 into the container. The diameter of the solder ball 3 is larger than the through hole 5 in the bottom surface of the container. Next, an excessive amount of the solder ball 3 is rolled in the container. Then, a part of the solder ball 3 falls into the through hole 5 and is held there. When all the through holes 5 hold the solder balls 3, the lid closing the collecting hole provided on the side surface of the container is removed, and the surplus solder balls 3 are discharged out of the board fixing jig 2 from the collecting holes. . At this time, in order to facilitate the holding of the solder balls, it is preferable that the through-hole 5 is formed in a tapered shape that spreads upward. The shape of the through-hole 5 can be changed by adjusting the shape of a molding die of alumina ceramic constituting the substrate fixing jig.
[0020]
While maintaining the positional relationship between the substrate fixing jig 2 and the insulating substrate 1 shown in FIG. 1B, the solder paste is melted, but the solder balls 3 are heated for a predetermined time at a temperature at which the solder balls 3 are not substantially melted (fourth). Process). When one of the solders having different melting points, such as the solder ball 3 and the solder paste, is melted, a so-called solder erosion phenomenon occurs on the other surface layer, and a new alloy layer is formed at the interface between the two. Merges. In the case of this example, all of the solder paste and the surface layer of the solder ball 3 are fused. In the present specification, including such a fusion state of the solder balls 3, it is expressed as “the solder balls 3 do not substantially melt”. If the fusion is not sufficient, it is preferable to previously provide a layer having substantially the same composition as the solder paste or a layer having substantially the same melting point on the surface of the solder ball 3 by barrel plating or the like. A similar fusion phenomenon also occurs for the land 6 and the solder paste on which the thick film is formed. If the land 6 and the solder paste are not sufficiently fused, it is preferable to previously provide a layer having substantially the same composition as the solder paste or a layer having substantially the same melting point on the surface of the land 6 by electroless plating or the like.
[0021]
By cooling the substrate fixing jig 2 and the insulating substrate 1 that have been heated and fused in this manner by leaving them at room temperature or the like, the fused state is fixed and becomes stable (fifth step). As described above, all the steps of the method for manufacturing an electronic component using the solder ball of the present invention are completed, and the electronic component according to the present invention can be obtained. If necessary, individual electronic components can be obtained by applying a stress in the opening direction of all the dividing grooves provided on the insulating substrate 1 and dividing the parts. Here, “as needed” means that, depending on the size of the substrate fixing jig 2, such a dividing step is performed after passing through all the steps shown in FIG. 2, and then the third to fifth steps are performed. This is in consideration of the possibility of implementation.
[0022]
In the method for manufacturing an electronic component using the solder ball of the present invention, in consideration of mass productivity, the third to fifth steps are preferably a series of steps while transporting the insulating substrate 1 and the substrate fixing jig 2. . A specific example of the process will be described with reference to FIG. The conveying means is a conveying device 13 including a commercially available belt conveyor. On the upper surface of the transfer device 13, the work is transferred from left to right in FIG. The point A on the upper surface of the transfer device 13 is a point where the substrate fixing jig 2 holding the solder balls 3 is placed. The point B is a point where the insulating substrate 1 having undergone all the steps shown in FIG. 2 is fitted into the opening of the substrate fixing jig 2 as shown in FIG. Since it may be difficult to position the insulating substrate 1 and the substrate fixing jig 2 in such a fitting step, it is preferable to perform the fitting step with the transport of the transport device 13 stopped once. In addition, it is preferable to use an image processing technique for the alignment. In this case, it is conceivable that the surface of the insulating substrate 1 where the lands 6 are not formed is sucked and held, and the lifting and movement of the insulating substrate 1 are numerically controlled. It is considered that such suction holding can be easily realized because the surface of the insulating substrate 1 is substantially smooth.
[0023]
When the third step at the point B is completed, the insulating substrate 1 and the substrate fixing jig 2 enter the reflow furnace 12 by the operation of the transfer device 13. Here, the above-mentioned solder paste, land 6 and solder ball 3 are fused (fourth step). Then, by the further operation of the transfer device 13, the insulating substrate 1 and the substrate fixing jig 2 leave the reflow furnace 12 and are left at room temperature, are naturally cooled, and the solder paste is solidified (stabilized) (fifth step). . When it is time to cool sufficiently, the insulating substrate 1 and the substrate fixing jig 2 are collected at the point C. Thus, the third to fifth steps could be made a series of steps.
[0024]
In the present embodiment, a method for manufacturing a network resistor having a common electrode 11 as an electronic component has been described. However, it goes without saying that the present invention is not limited to this. In addition, the present invention can be applied to a case where the element of the electronic component is a resistance element and / or a capacitor element, and the element is formed on the surface of the insulating substrate 1 as a multiple or network element.
[0025]
Further, in the present example, the third to fifth steps are performed with the positional relationship in which the insulating substrate 1 is placed on the substrate fixing jig 2, but it goes without saying that the positional relationship can be reversed. However, the positional relationship of the present embodiment is preferable in that the self-weight of the solder ball 3 makes the height of the solder ball 3 protruding from the insulating substrate 1 more uniform.
[0026]
In this example, “means for keeping the relative positional relationship between the insulating substrate 1 and the substrate fixing jig 2 in a direction along the surface of the insulating substrate 1 and / or the substrate fixing jig 2” is used. Although the outer end of the insulating substrate 1 is fitted to the opening of the substrate fixing jig 2 shown in FIG. 1A, it goes without saying that the present invention is not limited to such means. For example, it is preferable to use a fixing member.
[0027]
Further, in this example, the insulating substrate 1 is provided with a dividing groove, and a stress is applied in a direction in which the groove is opened to divide the insulating substrate 1 to obtain the insulating substrate 1 of each electronic component size from the large insulating substrate 1. Needless to say, the division means is not limited to this. For example, a so-called dicing method in which a diamond blade is rotated at a high speed to cut the insulating substrate 1 can be used. In this case, the large-sized insulating substrate 1 does not need a groove.
[0028]
【The invention's effect】
According to the present invention, the solder balls can be securely fixed to the smooth surface of the insulating substrate. Further, the height of the solder ball of the electronic component using the solder ball can be made uniform.
[Brief description of the drawings]
FIG. 1A is a perspective view showing a state before an insulating substrate and a substrate fixing jig according to the present invention are fitted together, and FIG. 1B is a perspective view showing a state where the insulating substrate and the substrate fixing jig are fitted together. It is a sectional outline figure after.
FIG. 2 is a diagram illustrating a part of the embodiment of the present invention and is a diagram illustrating a process of forming an element on an insulating substrate surface.
FIG. 3 is a diagram showing an example of how the third to fifth steps according to the present invention are formed as a series of steps.
FIG. 4 is a view showing a conventional technique for fixing a solder ball to a smooth surface of an insulating substrate.
[Explanation of symbols]
1. 1. Insulating substrate 2. Board fixing jig Solder ball4. Conductive paste5. Through hole 6. Land 7. Resistor 8. Glass 9. Trimming groove 10. Overcoat 11. Common electrode 12. Reflow furnace 13. Transfer device 51. Insulating substrate 52. Substrate fixing jig53. Solder ball 54. Conductor paste

Claims (11)

A method of manufacturing an electronic component using a solder ball, wherein an insulating substrate surface constituting the electronic component is substantially smooth, has an electrode land at a predetermined position on the insulating substrate surface, and a solder ball is fixed on the land. And
The insulating substrate surface and / or the substrate fixing jig has means for keeping a relative positional relationship between the insulating substrate and the substrate fixing jig in a direction along the insulating substrate surface,
The substrate fixing jig has means for holding a solder ball at a position facing the land when the fixed positional relationship is set,
A first step of disposing a conductive paste on the land;
A second step of holding the necessary amount of solder balls on the board fixing jig;
After passing through the second step, the insulating substrate passed through the first step is mounted on a substrate fixing jig having a constant positional relationship with the insulating substrate so that the conductive paste and the solder balls are in contact with each other. Process and
A fourth step of heating the insulating substrate and the substrate fixing jig that have undergone the third step, while maintaining the mounted state, in which the conductive paste is modified and the solder balls are not substantially melted;
And a fifth step of stabilizing the modified conductive paste after the fourth step. A method for manufacturing an electronic component using a solder ball, comprising: 2. The method for manufacturing an electronic component using solder balls according to claim 1, wherein the conductive paste is a solder paste or a conductive adhesive. 3. The method for manufacturing an electronic component using solder balls according to claim 1, wherein the elements of the electronic component are arranged on the same insulating substrate surface having the electrode lands. The method for manufacturing an electronic component using a solder ball according to claim 1, wherein the electrode lands are formed with a thick film. The solder ball according to claim 1, wherein the element of the electronic component is a resistance element and / or a capacitor element, and the element is formed on a surface of the insulating substrate as a multiple or network element. A method of manufacturing an electronic component to be used. The means for keeping the relative positional relationship between the insulating substrate and the substrate fixing jig constant is fitting of the insulating substrate into an opening of the substrate fixing jig, according to any one of claims 1 to 5, wherein An electronic component manufacturing method using solder balls. The means for holding the solder ball, which the substrate fixing jig has, is that the substrate fixing jig portion at a plurality of positions to hold the solder ball has a concave portion or a through hole having a size capable of holding the solder ball, The method for manufacturing an electronic component using a solder ball according to claim 1, wherein a part of the solder ball is exposed above the concave portion or the through hole in the holding state. 8. The method for manufacturing an electronic component using a solder ball according to claim 7, wherein a solder ball suction hole is provided in the recess, and the suction hole communicates with the outside of the substrate fixing jig. A mechanism is provided that supplies more solder balls than necessary to the substrate fixing jig before the second step, and collects excess solder balls from the substrate fixing jig after the second step and before the third step. A method for manufacturing an electronic component using the solder ball according to claim 1. The method of manufacturing an electronic component using a solder ball according to any one of claims 1 to 9, wherein the third to fifth steps are performed in a positional relationship in which the insulating substrate is placed on a substrate fixing jig. 11. The method for manufacturing an electronic component using a solder ball according to claim 1, wherein the third to fifth steps are a series of steps while transporting the insulating substrate and the substrate fixing jig. .

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