JP3430910B2 - Cream solder printing apparatus and solder bump forming method for forming solder bumps - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cream solder printing apparatus for printing cream solder for forming solder bumps on electrodes of substrates and electronic parts, and a solder bump forming method for forming solder bumps on these electrodes. It is a thing.

[0002]

2. Description of the Related Art As a method of soldering a substrate or an electronic component, a method of forming a solder bump on an electrode of the substrate or the electronic component in advance and performing the soldering by the solder bump is widely used. When forming this solder bump, solder is supplied by a method of printing cream solder on the electrode or a method of mounting a solder ball, and then the heated solder is melted on the electrode to form a solder on the electrode. Solder bumps are formed.

[0003]

By the way, since the soldering is to electrically connect the electronic parts constituting the electronic circuit, the soldering portion must be completely conductive,
Therefore, abnormalities such as partial missing of solder bumps cannot be tolerated.

However, in the process of forming the solder bumps, it is difficult to completely eliminate abnormalities such as partial missing of the solder bumps and size reduction, and the frequency is low (about 0.1% in the past results). However, an abnormality occurs. This is because in the method of printing cream solder, the cream solder may remain in the pattern holes of the mask plate used for printing and may not be completely printed on the electrodes. It is because solder balls remain attached to the suction tool during mounting and it is easy to make a mounting error that is not completely mounted on the electrode, and it is actually difficult to completely remove these factors. is there.

Therefore, in the conventional solder bump forming method, an inspection is performed after forming the solder bumps in order to guarantee reliability in quality, and if an abnormality of the solder bumps is found by the inspection, it is an expensive product. Nevertheless, most of them had to be disposed of as defective products due to quality assurance requests. As described above, the conventional method of forming solder bumps has a problem that defective products due to abnormalities of the solder bumps are unavoidable, and there is a limit to improvement of the overall yield.

It is therefore an object of the present invention to provide a cream solder printing apparatus and a solder bump forming method capable of reducing abnormalities of solder bumps and improving yield.

[0007]

According to another aspect of the present invention, there is provided a cream solder printing apparatus for forming solder bumps, wherein a mounting portion on which a substrate or an electronic component is mounted, and a solder amount corresponding to a volume of a solder bump having a regular shape. A mask plate having an inner volume capable of accommodating a cream solder containing, and provided with a pyramidal pattern hole that substantially circumscribes a regular-shaped solder bump, and the solder bump on the mounting portion is formed on the mask plate. Elevating means for moving up and down relatively to the board or electronic component, application means for applying cream solder on the mask plate mounted on the board or electronic component, and moving while sliding on the mask plate And a squeegee for filling the pattern holes with cream solder.

According to a second aspect of the present invention, there is provided a cream solder printing apparatus for forming solder bumps, in which a mounting portion for mounting a substrate or an electronic component and a cream solder containing a solder amount corresponding to a volume of a regular shaped solder bump are accommodated. A mask plate having an inner volume that can be formed and having a substantially cylindrical pattern hole that is lower than the height of a regular-shaped solder bump, and the mask plate with respect to the substrate or the electronic component on which the solder bump on the mounting portion is formed. And elevating means for relatively elevating and lowering, a extending means for extending a solder bump protruding from the pattern hole on the mask plate mounted on the substrate or the electronic component to close an upper portion of the pattern hole, and the mask Application means for applying cream solder on the plate, and moving while sliding on the mask plate to fill the pattern holes with the cream solder. And a Chigi.

According to a third aspect of the present invention, there is provided a solder bump forming method, wherein after forming a solder bump on a substrate or an electronic component, the solder bump is formed on an electrode of the substrate or the electronic component where the solder bump is abnormal. A bump forming method, wherein a pyramidal shape having an inner volume capable of accommodating a cream solder including a solder amount corresponding to the volume of a regular-shaped solder bump on the substrate or the electronic component and substantially circumscribing the regular-shaped solder bump. Mounting a mask plate having pattern holes, and supplying the cream solder to the electrodes having abnormal solder bumps by printing the cream solder on the mask plate, and then heating the substrate or electronic component. Thus, the cream solder was melted and solidified on the electrodes to form solder bumps.

According to a fourth aspect of the present invention, there is provided a solder bump forming method, wherein after forming a solder bump on a substrate or an electronic component, the solder bump is formed on an electrode of the electrode of the substrate or the electronic component having an abnormal solder bump. A bump forming method, wherein the substrate or the electronic component has a substantially cylindrical shape having an inner volume capable of accommodating a cream solder including a solder amount corresponding to the volume of a regular-shaped solder bump and having a lower height than a regular-shaped solder bump. Attach the mask plate with the pattern holes of
After the solder bumps protruding from the pattern holes are extended by the extension means to block the upper surface of the pattern holes, cream solder is printed on the mask plate to supply the cream solder to the electrodes having the abnormality of the solder bumps. Then, the cream solder is melted and solidified on the electrodes by heating the electrodes or the substrate to form solder bumps.

According to the invention described in each claim, a mask plate having a pattern hole having a shape in which cream solder does not enter is attached to the electrode on which the solder bump having a regular shape is formed, and the cream solder is placed on the mask plate. By printing, the cream solder can be supplied only to the electrodes having abnormalities such as an undersized or missing solder bump to form a normal solder bump.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment 1) FIG.
3B, 3C, and 3D are process explanatory diagrams of the solder bump forming method according to the first embodiment of the present invention, FIG. 2 is a side view of the cream solder printing apparatus, and FIGS. ), (C),
(D) is a process explanatory view of the same solder bump forming method.

First, in FIG. 1A, an electrode 2 for forming a solder bump is provided on the upper surface of a substrate 1. The substrate 1 is aligned with the mask plate 3 provided with the pattern holes 4 corresponding to the electrodes 2, and the mask plate is mounted on the substrate 1.

Next, as shown in FIG. 1 (b), after applying the cream solder 5 on the mask plate 3, the squeegee 6 is slid on the mask plate 3 so that the cream solder 5 is placed in the pattern holes 4. Is printed. And Figure 1
As shown in (c), by separating the mask plate 3 and the substrate 1, the cream solder 5 in the pattern hole 4 escapes from the pattern hole 4 and is supplied onto the electrode 2. At this time, the cream solder 5 remains in the pattern hole 4 due to defective printing of the cream solder 5 from the pattern hole 4, and the electrode 2
The cream solder may not be supplied on top.

After that, the substrate 1 is sent to a reflow furnace and heated. As a result, the cream solder 5 on each electrode 2 is melted, and the molten solder is solidified to form solder bumps 5'as shown in FIG. 1D, but the above-mentioned cream solder 5 is not supplied. In the electrode 2, the solder bump 5'is missing. Since the solder bumps 5 ′ are formed by additionally adding solder bumps to the missing electrodes where the solder bumps 5 ′ are missing, the cream solder 5 is printed again by the cream solder printing apparatus described below.

Here, the cream solder printing apparatus will be described. As shown in FIG. 2, the substrate 1 on which the solder bumps 5 ′ are formed is placed on the placing portion 10. A mask plate 7 is arranged above the substrate 1. Placement part 1
0 can be moved up and down relatively with respect to the mask plate 7 by a cylinder 9 as an elevating means. The mask plate 7 is provided with conical pattern holes 8 corresponding to the positions of the electrodes 2. By driving the cylinder 9 to raise the substrate 1 with respect to the mask plate 7,
The mask plate 7 is mounted on the substrate 1.

The shape dimensions of the pattern holes 8 are set so as to satisfy the following conditions. That is, in a state where the mask plate 7 is mounted on the substrate 1, the inner surface of the pattern hole 8 is substantially circumscribed with the outer periphery of the regular-shaped solder bump 5 ′ already formed on the electrode 2, and the inner surface of the pattern hole 8 is Solder bump 5 '
The gap created partially with the outer periphery of the cream solder 5
The shape dimension of the pattern hole 8 is set so as to be smaller than the size of the solder particles contained therein. Further, the inner volume of the pattern hole 8 can accommodate the cream solder 5 including the solder amount corresponding to the volume of the regular-shaped solder bump 5 ′.

Above the mask plate 7, a dispenser 11 which is a means for applying the cream solder 5 is arranged. The dispenser 11 applies the cream solder 5 onto the mask plate 7 mounted on the substrate 1. A squeegee 12 is provided on the mask plate 7. By sliding the squeegee 12 with the cream solder 5 applied on the mask plate 7, the cream solder 5 is filled in the pattern holes 8 located on the missing electrodes 2.

The cream solder printing apparatus for forming solder bumps is configured as described above, and the cream solder printing for forming bumps will be described below. As shown in FIG. 3 (a), the solder bumps 5 ′ mounted on the mounting portion are already formed, and the substrate 1 including the missing electrodes 2 is attached to the mask plate 7 by the cylinder 9 (FIG. 2). The substrate 1 is lifted and the substrate 1 is aligned and mounted on the mask plate 7 as shown in FIG. After that, the cream solder 5 is applied on the mask plate 7 by the dispenser 6, and then the squeegee 11 is applied.
Is slid on the mask plate 7 to print the cream solder in the pattern hole 8 located on the missing electrode 2.

At this time, since the solder particles in the cream solder 5 cannot penetrate into the pattern holes 8 in which the solder bumps 5'are already properly formed, the cream adhered to the solder bumps 5'having a regular shape is formed. A small amount of solder 5 is present. Then, by separating the substrate 1 and the mask plate 7, the cream solder 5 corresponding to the solder amount of the regular-shaped solder bump 5 ′ is supplied onto the missing electrode 2 as shown in FIG. 3C.

After that, the substrate 1 is sent to a reflow furnace, where the substrate 1 is heated. As a result, the cream solder 5 on the missing electrode 2 is melted, and then cooled and solidified to form the state shown in FIG.
As shown in FIG. 5, a solder bump 5 ′ having a regular shape is formed on the electrode 2. At this time, the solder bumps 5'which have already been normally formed are also melted at the same time, cooled, and then again solder bumps 5 '.
To form.

The above description shows a case where the cream solder 5 is not supplied onto a certain electrode 2 at all, and the solder bump 5'is completely missing, but the cream solder 5 on the electrode 2 is abnormal. Even when only a small amount of solder bumps are supplied, and as a result, an excessively small solder bump is formed, a solder bump having a regular shape can be formed by the same method as described above. That is, in the pattern hole 8 located in the electrode 2 on which the solder bump of which size is too small is formed, a gap is formed between the solder bump and the pattern hole 8. Therefore, when the cream solder 5 is printed, the cream solder 5 enters the gap and adheres to the solder bumps having an undersized size to supplement the amount of solder. Then, by reheating, the solder bumps and the cream solder attached to the solder bumps are fused, and after cooling and solidification, the solder bumps 5'having a normal shape and having a normal amount of solder can be formed.

In the first embodiment, the cream solder 5 is first printed and the solder bump 5'is formed by supplying the solder to the electrode 2. However, first, the solder bump 5'is formed. The forming method is not limited to this, and other methods such as a method of mounting solder balls on the electrodes 2 and supplying solder may be used.

(Second Embodiment) FIG. 4 is a side view of a cream solder printing apparatus according to a second embodiment of the present invention, FIG.
6B, 6C, 6A, 6B, and 6C are process explanatory diagrams of the solder bump forming method according to the second embodiment of the present invention.

First, a cream solder printing apparatus according to a second embodiment of the present invention will be described with reference to FIG. In FIG. 4, the substrate 1 on which the solder bumps 5 ′ are formed is placed on the placing portion 10. A mask plate 13 is arranged above the substrate 1. The mounting portion 10 can be moved up and down relatively with respect to the mask plate 13 by a cylinder 9 which is a lifting means. The mask plate 13 is provided with pattern holes 14 corresponding to the positions of the electrodes 2.

The pattern dimension of the pattern hole 14 is a substantially cylindrical shape having a height dimension t lower than the height h of the regular-shaped solder bump 5 ', and includes the amount of solder corresponding to the volume of the solder bump 5'. It has an internal volume that can accommodate the cream solder 5. The cylinder 9 is driven to drive the mask plate 13
By raising the substrate 1 with respect to the mask plate 13, the mask plate 13 is mounted on the substrate 1.

Above the mask plate 13, the roller 1 is provided.
5 are provided. By rolling the roller 15 on the mask plate 13 with the mask plate 13 mounted on the substrate 1, the roller 15 presses the upper ends of the solder bumps 5 ′ protruding from the pattern holes 14 to extend them. The extended solder bump 5 ′ is crushed and deformed as described later to close the upper portion of the pattern hole 14.

A dispenser 11 which is a means for applying the cream solder 5 is arranged above the mask plate 13. The dispenser 11 applies the cream solder 5 onto the mask plate 13 mounted on the substrate 1. A squeegee 12 is provided on the mask plate 13. By sliding the squeegee 12 with the cream solder 5 applied on the mask plate 13, the cream solder 5 is filled in the pattern holes 14 located on the missing electrodes 2.

This cream solder printing apparatus is configured as described above, and the cream solder printing for forming solder bumps will be described below. As shown in FIG. 5A, the mounting portion 10
(FIG. 4) The substrate 1 having the solder bumps 5 ′ mounted thereon and the missing electrodes 2 is already formed on the cylinder 9 (FIG. 4).
To the mask plate 13 by
As shown in (b), the substrate 1 is aligned with and mounted on the mask plate 13.

Then, the solder bumps 5'in the pattern holes 14 are formed.
5 with the upper part of the mask protruding above the mask plate 13.
As shown in (c), the roller 15 which is a spreading means is pressed against the mask plate 13 to roll. As a result, the upper portion of the solder bump 5 ′ is crushed and expanded by the roller 15 and the upper portion of the pattern hole 14 is blocked.
That is, by appropriately setting the hole diameter and the height dimension t of the pattern hole 14, as described above, the cream solder 5 containing the solder having the inner volume of the pattern hole 14 in an amount corresponding to the solder amount of the solder bump 5 ′ of the regular shape is formed. The volume of the solder bumps 5 ′ may be substantially the same as the volume of the solder bumps 5 ′, and the upper portions of the pattern holes 14 may be closed with the solder bumps 5 ′ extended by the rollers 15.

Next, as shown in FIG. 6A, the cream solder 5 is applied on the mask plate 13, and the squeegee 12 is slid to print the cream solder 5. As a result, the cream solder 5 is placed in the pattern hole 14 located at the missing electrode.
Is filled, and then the mask plate 13 and the substrate 1 are separated, so that the cream solder 5 is supplied onto the missing electrode 2 as shown in FIG. 6B. At this time, since the upper part of the pattern hole 14 on the electrode 2 on which the solder bump 5 ′ has already been formed is closed by the extended solder bump 5 ′, the cream solder 5 is supplied only on the missing electrode 2. It

After that, by heating the substrate 1 in a reflow furnace, the solder bumps 5'and the cream solder 5 are melted, and the molten solder is cooled and solidified.
As shown in FIG. 3, solder bumps 5 ′ having a regular shape are formed on all the electrodes 2. Note that the bump forming method according to the second embodiment is applicable to solder bumps having an undersized size, and the first solder bump forming method is limited to the method of supplying solder by printing the cream solder 5. What is not done is the same as in the first embodiment.

As shown in each of the above-mentioned embodiments, the shape of the pattern holes of the mask plate is set so that the cream solder can be supplied only to the electrodes of the solder bumps that are abnormal such as missing or undersized. Solder bumps are mounted on a board that has been determined to have an abnormality, and by printing cream solder, the required amount of cream solder can be applied to the required locations without individually identifying the electrodes with abnormal solder bumps. Can be supplied. Therefore, it becomes possible to efficiently repair the board judged to have an abnormality in the solder bump, and as a result, the board and electronic components that were previously discarded as defective products are made good and can be reused effectively. Therefore, the product yield can be improved.

In addition, it is not necessary to specify the electrode having the abnormality of the solder bump as described above, in other words, it is possible to omit the visual inspection for the purpose of detecting the abnormality related to the presence or the size of the solder bump. is doing. That is, assuming that the solder bump forming method of each of the above-described embodiments is applied after the solder bumps are first formed, a series of steps involved in the inspection / repair, that is, the electrode having the solder bump abnormality is identified. However, it is possible to omit the step that requires complicated management of separating the substrate having the electrode and sending it to a repair step to repair the electrode of the substrate. As described above, the abnormality occurrence rate in the solder bump formation process is on the order of 0.1%, and by repeating this process twice, the final abnormality occurrence rate is actually reduced to a level close to zero. It can be done.

Of course, when the abnormality of the solder bump can be easily detected by the inspection, the above-described method of forming the solder bump may be applied only to the one determined to have the abnormality. Even in this case, the efficiency of repair work can be improved because a simple process of cream solder printing and heating by reflow is simply added without specifying a repair location.

[0036]

According to the present invention, a mask plate having a pattern hole having a shape in which cream solder does not enter is attached to an electrode on which a solder bump having a regular shape is formed, and cream solder printing is performed on this mask plate. As a result, cream solder can be printed and supplied only to the electrodes with abnormalities such as undersized or missing solder bumps.
It is possible to efficiently repair the solder bump abnormality. Therefore, it is possible to make a substrate or an electronic component, which has been conventionally disposed of as a defective product, discarded as a defective product, and to effectively reuse the substrate or the electronic component, and to improve the product yield.

[Brief description of drawings]

FIG. 1A is a process explanatory diagram of a solder bump forming method according to a first embodiment of the present invention. FIG. 1B is a process explanatory diagram of a solder bump forming method according to a first embodiment of the present invention. Process explanatory drawing of the solder bump forming method of form 1 (d) Process explanatory drawing of the solder bump forming method of Embodiment 1 of this invention

FIG. 2 is a side view of the cream solder printing apparatus according to the first embodiment of the present invention.

3A is a process explanatory view of the solder bump forming method of the first embodiment of the present invention. FIG. 3B is a process explanatory view of the solder bump forming method of the first embodiment of the present invention. Process explanatory drawing of the solder bump forming method of form 1 (d) Process explanatory drawing of the solder bump forming method of Embodiment 1 of this invention

FIG. 4 is a side view of the cream solder printing apparatus according to the second embodiment of the present invention.

5A is a process explanatory diagram of a solder bump forming method according to a second embodiment of the present invention. FIG. 5B is a process explanatory diagram of a solder bump forming method according to a second embodiment of the present invention. Process explanatory drawing of solder bump forming method of form 2

6A is a process explanatory diagram of a solder bump forming method according to a second embodiment of the present invention. FIG. 6B is a process explanatory diagram of a solder bump forming method according to a second embodiment of the present invention. Process explanatory drawing of solder bump forming method of form 2

[Explanation of symbols]

1 substrate 2 electrodes 3,7,13 Mask plate 4, 8, 14 pattern holes 5 cream solder 5'solder bump 6, 11 squeegee 9 cylinders 10 Placement section 12 dispensers 15 Laura

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-7-307562 (JP, A) Utility model registration 3042814 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H05K 3 / 34 B41F 15/08 B41F 15/40 H01L 21/60 H01L 23/12

Claims (4)

(57) [Claims] 1. A mounting portion for mounting a substrate or an electronic component,
A mask plate having an inner volume capable of accommodating a cream solder containing an amount of solder corresponding to the volume of a regular-shaped solder bump, and having a conical-shaped pattern hole that substantially circumscribes the regular-shaped solder bump, and the mask plate. Elevating means for moving up and down relative to a substrate or electronic component on which solder bumps are formed on the mounting portion, and application means for applying cream solder onto the mask plate mounted on the substrate or electronic component And a squeegee that slides on the mask plate and fills the pattern holes with cream solder, the cream solder printing apparatus for forming solder bumps. 2. A mounting portion for mounting a substrate or an electronic component,
A mask plate having an inner volume capable of accommodating a cream solder containing an amount of solder corresponding to the volume of a regular-shaped solder bump and having a substantially cylindrical pattern hole lower than the height of the regular-shaped solder bump, and the mask plate Elevating means for moving up and down relative to a substrate or electronic component on which solder bumps are formed on the mounting portion, and solder protruding from the pattern hole on the mask plate mounted on the substrate or electronic component Extending means for extending the bump to close the upper portion of the pattern hole, applying means for applying cream solder on the mask plate, and moving while sliding on the mask plate to put the cream solder in the pattern hole. A cream solder printing apparatus for forming solder bumps, comprising a squeegee to be filled. 3. A method of forming a solder bump, comprising forming a solder bump on a substrate or an electronic component, and then forming the solder bump on an electrode of the electrode of the substrate or the electronic component where the solder bump is abnormal. Alternatively, a mask plate having an inner volume capable of accommodating a cream solder containing an amount of solder corresponding to the volume of a regular-shaped solder bump and having a conical-shaped pattern hole that substantially circumscribes the regular-shaped solder bump is provided on the electronic component. After mounting, the cream solder is printed on the mask plate to supply the cream solder to the electrodes, and then the substrate or the electronic component is heated to melt and solidify the cream solder on the electrodes to form solder bumps. A method for forming solder bumps, which comprises forming the solder bumps. 4. A solder bump forming method, comprising forming solder bumps on a substrate or an electronic component, and then forming the solder bumps on electrodes having abnormal solder bumps among electrodes of the substrate or electronic component. Alternatively, a mask plate having an approximately cylindrical pattern hole having an inner volume capable of accommodating cream solder containing a solder amount corresponding to the volume of a regular-shaped solder bump and having a substantially cylindrical pattern hole having a lower height than the regular-shaped solder bump is provided on the electronic component. After mounting, the solder bumps protruding from the pattern holes are spread by a spreading means to close the upper surface of the pattern holes, and then cream solder is printed on the mask plate to apply the cream to the electrodes having the abnormal solder bumps. Forming solder bumps by melting and solidifying the cream solder on the electrodes by supplying solder and then heating the substrate or electronic component. Solder bump forming method according to claim.