JP2002144526A - Method of supplying solder paste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of ensuring supply of solder paste of a proper kind to a desired area on the same substrate by screen printing. SOLUTION: On the substrate 3 having a plurality of areas 4 and 5, a first mask 1a having openings 14a and 15a corresponding respectively to the areas 4 and 5 is provided, and further a second mask 2a having an opening 24 corresponding to the area 4 out of the areas 4 and 5 is put thereon. By a squeegee 31 disposed on the top of the second mask, a first solder paste 41 is pressed into openings 24a and 14a and supplied to the area 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for supplying solder on a substrate of an electronic device, and more particularly, to a method for supplying cream solder by screen printing having a mask and a squeegee.

[0002]

2. Description of the Related Art Conventionally, a method of supplying cream solder onto a substrate by screen printing with a mask and a squeegee when forming a circuit of an electronic device has been used. First,
This conventional cream solder supply method will be described below with reference to the drawings.

FIG. 9 is a partial sectional view of a screen printing apparatus showing a conventional cream solder supply method. On a substrate 3 having a region 4 to which the cream solder 41 is supplied, a mask 1a having an opening 14a corresponding to the region is set,
The squeegee 31 is arranged on the upper surface. Here, mask 1
The cream solder 41 provided on the upper surface of a is moved while being scraped off by the movement of the squeegee 31 in the direction indicated by the broken arrow, and is pushed into the opening 14a of the mask 1a and supplied to the region 4 of the substrate 3. Thereafter, when the mask 1a is removed from the substrate 3, cream solder is formed in the region 4.

[0004]

However, in recent years, in consideration of the natural environment and the human body, there has been an active movement to eliminate the use of lead, which is particularly harmful.
There is a trend to use lead-free cream solder (hereinafter sometimes referred to as “lead-free solder”). Here, the general types and characteristics of this lead-free solder will be described below.

[0005] Lead-free solder is based on tin-zinc and tin-
It can be broadly classified into two types of solder, "silver + copper". The former is 19
It is a low-temperature melting point type solder that may be melted in a relatively low temperature range of about 5 ° C. to 230 ° C. (hereinafter sometimes referred to as “low-temperature type solder”), while the latter is about 220 ° C. to 250 ° C. It is a high-temperature melting point type solder that melts in a relatively high temperature range (hereinafter sometimes referred to as “high-temperature type solder”). In addition, since the latter high-temperature solder does not contain zinc, it has an excellent oxidation resistance.

Further, a general use range of these lead-free solders will be described. The low-temperature solder is a region where the electrical components mounted on the substrate have a high mounting density, for example, a region where an IC or a 1005 size chip is mounted, or a region on a GND pattern where heat during reflow is easily diffused. Used for On the other hand, the high-temperature solder is used in a region where high quality such as oxidation resistance is required, a region where mounting density is low, or a region where heat during reflow is difficult to diffuse.

The term "reflow" as used herein means that after screen printing for supplying cream solder has been completed (electrical components may be further mounted), the cream solder is melted by heating the entire substrate, and then cooled by cooling. This is a step of fixing the solder to a region on the substrate, which is a known technique.

In many practical substrates, a plurality of regions having different mounting densities and quality requirements of electric components are often present on the same substrate. However, since the above-mentioned conventional cream solder supply method can cope with only one kind of solder, if lead-free solder is to be applied, either low-temperature solder or high-temperature solder must be selected.

However, when only low-temperature solder is used for the substrate, the low-temperature solder is less oxidizable than the high-temperature solder, so that the requirements for a region where high quality is required are not satisfied. On the other hand, when only the high-temperature solder is used, it is necessary to sufficiently reflow the solder supplied particularly to the region where the mounting density is high, so that the heating temperature during the reflow is set to a high temperature within the melting temperature range of the high-temperature solder. Side. Then, there is a high risk that the mounted electric component such as an IC that is sensitive to heat will break down due to thermal influence.

Therefore, it is necessary to supply an appropriate type of cream solder to a desired area on a substrate having a plurality of areas having different mounting densities and quality requirements of electric components.
There is a strong demand for a cream solder supply method that can achieve this requirement.

For example, in Japanese Patent Application Laid-Open No. Hei 5-212852, a plurality of masks each having an opening in a part of a different region and having different thicknesses are prepared, and the cream solder is supplied a plurality of times using each of the masks. Thereby, cream solders having different thicknesses are formed in different regions on the same substrate. Using this method, it is also possible to supply different types of cream solder.

However, when supplying different types of cream solder to a plurality of areas close to each other, in this method,
It is premised that the thickness of the cream solder to be formed is different, and it is not appropriate to require that the thickness be constant. Because, in performing this method, the first
Secondly, the formed cream solder is interrupted so as not to be supplied with the second and subsequent cream solders. Second, the formed cream solder comes into contact with the bottom surface of the mask and is crushed, so that it is out of a desired area on the substrate. This is because in order to satisfy the essential condition of preventing the spread, the concave portion corresponding to the cream solder formed by the previous supply needs to be provided on the bottom surface of the mask used for the second and subsequent supply. If the thickness of the cream solder to be formed is constant, that is, if the thickness of the mask is constant, the concave portion cannot be provided so as to satisfy the above condition.

Therefore, according to this method, it is not possible to reliably supply an appropriate type of cream solder to a desired area on the same substrate without being restricted by the thickness of the cream solder to be formed and the area to be supplied.

The present invention has been made in view of the above problems, and has as its object to provide a method capable of reliably supplying a proper type of cream solder to a desired region on the same substrate by screen printing. Is what you do.

[0015]

In order to achieve the above object, a cream solder supply method according to the present invention is a method of supplying cream solder to a plurality of regions on a substrate by screen printing provided with a mask and a squeegee. Then, a first mask having an opening corresponding to each of the regions and a second mask having an opening corresponding to a part of the regions are overlaid in this order, and cream solder is supplied.

In order to supply different types of cream solder having a constant thickness to respective desired areas, the cream solder is supplied using the first mask and the second mask, and then only the second mask is applied to the substrate. From the first and the first
And another second mask having an opening corresponding to a part of the region that is different from the region corresponding to the opening of the second mask in this order, and the cream solder and Supply different kinds of cream solder.

In order to supply not only the type but also the cream solder having different thicknesses to the respective desired areas, the cream solder is supplied using the first mask and the second mask, and then the first mask and the second mask are supplied. Removing the second mask from the substrate, and further corresponding to another first mask thicker than the first mask and a part of the region different from the region corresponding to the opening of the second mask. Another second mask having an opening is placed in this order to supply a different type of cream solder from the cream solder.

From the viewpoint of removing excess solder immediately after the cream solder is supplied, after the cream solder is supplied, it is possible to remove the second mask in a planar direction while sliding the second mask with respect to the first mask. preferable. In order to further increase the certainty, for example, in the opening of the second mask, the cross-sectional shape on the opposite side to the sliding direction in which the second mask is removed is tapered in the searching direction toward the sliding direction. It is preferable that the side surface is inclined so that

In order to suppress the generation of excess cream solder, for example, it is preferable to form the second mask into a film.

Further, from the viewpoint of ensuring the accuracy of the position at which the cream solder is supplied, the substrate, the first mask, and the second
It is desirable to determine the position of the mask in the planar direction. For example, as the means, there are at least two projections provided on a holding member for holding the substrate, the first mask and the second mask.
It is preferable that a hole or a notch provided to correspond to each of the protrusions is engaged with the mask.

In consideration of the natural environment and the human body,
It is desirable that the plurality of types of cream solder be lead-free solder which is made lead-free.

[0022]

Embodiments of the present invention will be described below. First, a cream solder supply method according to a first embodiment of the present invention will be described with reference to partial cross-sectional views of a screen printing apparatus shown in FIGS. The cream solder supply method is divided into a first step of supplying the first cream solder 41 shown in FIG. 1 and a second step of supplying the second cream solder 42 shown in FIG.

First, in a first step, as shown in FIG. 1A, a region 4
5 is provided with a first mask 1a having openings 14a and 15a corresponding to each of the regions 4, and a second mask 2a having openings 24 corresponding to some regions 4 of the regions 4 and 5.
And the squeegee 31 is arranged on the upper surface. The regions 4 and 5 are conductor portions provided on the substrate 3 and are regions where cream solder is supplied. The cross section on the left including the region 4 and the cross section on the right including the region 5 are shown in FIG.
The cross sections are parallel and different from each other in the directions indicated by solid arrows in (b) and (c), and the respective regions do not coexist on each cross section.

Here, the first cream solder 41 provided on the upper surface of the second mask 2a moves while being scraped off by the movement of the squeegee 31 in the direction indicated by the dashed arrow.
Opening 24 of first mask 1a and opening 24 of first mask 1a
4 a and supplied to the region 4 of the substrate 3. At this time, the region 5 is not supplied because there is no opening in the second mask 2a.

Thereafter, as shown in FIGS. 1B and 1C, when the second mask 2a is moved in the direction shown by the solid line arrow while sliding with respect to the first mask 1a, the second mask 2a is supplied to the region 4. The cream solder 41 is divided into the cream solder 41a in the opening 14a of the first mask 1a and the cream solder 41b in the opening 24 of the second mask 2a.

When the second mask 2a is removed in the sliding direction as it is, the separated cream solder 41b
Is also removed together. Since the region 5 does not coexist on the left cross section including the region 4, the cream solder 41
b is not supplied to the opening 15a of the first mask 1a. Further, when the first mask 1a is removed, FIG.
As shown in (d), the cream solder 41 having the same thickness as the thickness t1a of the first mask 1a is provided only in the region 4 on the substrate 3.
a is formed.

Subsequently, in a second step, as shown in FIG. 2A, openings 14b and 15b corresponding to the regions 4 and 5 are formed on the substrate 3 after the first step. Then, a first mask 1b thicker than the first mask 1a used in the first step is provided. At this time, the cream solder 41a formed in the region 4 is applied to the opening 14 by the first mask 1b.
There is no deformation due to contact due to b. Further, a second mask 2b having an opening 25 corresponding to a region 5 different from the region 4 corresponding to the opening 24 of the second mask 2a among the regions 4 and 5 is superimposed, and a squeegee 32
Place.

Here, the second cream solder 42 provided on the upper surface of the second mask 2b is moved while being scraped off by the movement of the squeegee 32 in the direction shown by the dashed arrow.
Opening 25 of mask 2b and opening 1 of first mask 1b
5b and supplied to the region 5 of the substrate 3. At this time, the region 4 is not supplied because there is no opening in the second mask 2b.

Then, as shown in FIGS. 2B and 2C, when the second mask 2b is moved in the direction shown by the solid line arrow while sliding with respect to the first mask 1b, the second mask 2b is supplied to the region 5. The cream solder 42 thus cut is divided into a cream solder 42a in the opening 15b of the first mask 1b and a cream solder 42b in the opening 25 of the second mask 2b.

When the second mask 2b is removed in the sliding direction as it is, the separated cream solder 42b
Is also removed together. Further, when the first mask 1b is removed, a cream solder 41a having the same thickness as the thickness t1a of the first mask 1a is formed in the region 4 on the substrate 3, as shown in FIG. The cream solder 42a having the same thickness as the thickness t1b of the first mask 1b is formed in the region 5, and the process is completed.

Therefore, the supplied first cream solder 4
If the types of the first and second cream solders 42 are changed, cream solders of different types and thicknesses can be formed on the same substrate. In the first and second steps, the second masks 2a and 2b are replaced with the first masks 1a and 1a, respectively.
The direction of sliding movement with respect to b is not limited as long as different areas do not overlap on a cross section parallel to the sliding direction. The first masks 1a and 1b and the second masks 2a and 2b are generally made of metal, but are not damaged by sliding movement of the squeegees 31 and 32 and the second masks 2a and 2b. Any material may be used as long as it has the above strength.

However, the thickness t of the first masks 1a and 1b
Regarding 1a and t1b, it is desirable that the relationship of t1a <t1b be established. This is to prevent the first cream solder 41b formed in the region 4 in the first step from excessively contacting the lower surface of the second mask 2b in the second step.

The thickness t1 of the first masks 1a and 1b
If a and t1b have the same thickness, that is, if only one sheet is used throughout without preparing a plurality of sheets as the first mask, the thickness of the cream solder to be formed becomes constant. Is constant, and different types of cream solder can be formed. In addition, since the replacement of the first mask can be omitted, not only the work efficiency is improved, but also the manufacturing cost of the mask can be suppressed.

Further, in response to a demand for forming cream solder of a different thickness with a constant thickness, the second mask is used as an opening corresponding to a part of a plurality of different regions of the substrate. It is sufficient to prepare a plurality of masks having the above, and increase the number of the steps. Further, in response to a demand for forming cream solders having further different thicknesses, a plurality of masks having the openings are prepared as the second masks, and masks having different thicknesses are further used as the first masks. This can be achieved by preparing a plurality of sheets and increasing the number of steps.

Further, by combining these, a plurality of regions having a constant thickness and different types of cream solder, a plurality of regions having different thicknesses and different types of cream solder, or the same type of cream solder are formed on the same substrate. It is also possible to mix a plurality of regions having different thicknesses.

In the first and second steps, the second masks 2a and 2b are respectively replaced with the first mask 1a.
Although it is designed to be removed while sliding with respect to a and 1b, the following advantages can be obtained by doing so. In other words, as shown in FIG. 1B, immediately after the supply of the first cream solder 41 is performed, the cream solder 41 supplied to the region 4 is placed on the second mask from the upper surface of the first mask 1a. The mask 2a protrudes by the thickness t2a (corresponding to the cream solder 41b in FIG. 1C). If the cream solder 41b remains, excessive contact with the lower surface of the second mask 2b having no opening corresponding to the region 4 is caused in the second step, and the first mask 1
2b becomes unstable.

Accordingly, the cream solder 41b is an unnecessary surplus cream solder and is desirably removed. Therefore, the second mask 2a is replaced with the first mask 1a.
By removing the solder cream 41b while sliding it, the excess cream solder 41b can be removed while being divided, and this requirement can be achieved.

Further, when such removal is performed,
The thickness of the cream solder 41a formed in the opening 14a of the first mask 1a is equal to the thickness t1 of the first mask 1a.
a. Therefore, the formed cream solder 41
The thickness adjustment of a can be performed only by adjusting the thickness of the first mask 1a regardless of the thickness t2a of the second mask 2a,
Management can be performed easily. In the second step, such removal is effective for the same reason.

As described above, in FIG. 1B, the cream solder 41b (see FIG. 1C) in the opening 24 of the second mask included in the cream solder 41 supplied to the region 4 is removed. Therefore, it may be required to suppress the generation amount. Therefore, it is noted that the amount of the excess cream solder 41b is correlated with the thickness t2a of the second mask 2a. For example, the second mask 2a is formed into a thin film having a thickness t2a. Then, since the excess cream solder 41b is generated only in a thin film-shaped sludge, the amount to be removed can be small and the loss cost can be reduced.

Moreover, even if the surplus cream solder 41b remains without being removed, it does not cause excessive contact with the second mask 2b in the second step (see FIG. 2A). Mask 2b to mask 1b
Is stable. Therefore, in the first step, the second mask 2a is removed while sliding with respect to the first mask 1a, but this can be omitted.

Further, when the second mask 2a is formed into a film shape as described above, the cream solder 41 supplied to the area 4 is formed.
Is substantially the same as the thickness t1a of the first mask 1a, so that the thickness of the cream solder formed only by adjusting the thickness of the first mask 1a can be adjusted, and the management can be easily performed. . In the second step, it is effective to form the second mask 2b into a film for the same reason.

Next, a second embodiment of the present invention will be described. As described above, in FIGS. 1 and 2, the excess cream solders 41b and 42b are removed while being held in the openings 24 and 25 by the sliding movement of the second masks 2a and 2b. First masks 1a, 1
The second embodiment is a method for surely removing it because there is a possibility of remaining on b.

For example, as shown in FIG. 3A, the second mask 2 is formed in the opening 24 of the second mask 2a.
The side surface 24a is inclined so that the cross-sectional shape on the opposite side to the sliding direction (indicated by the solid arrow) from which the a is removed is tapered in the depth direction toward the sliding direction. Here, FIG.
As shown in (b), the cream solder 41b separated by the sliding movement of the second mask 2a is
a gradually rises along the side surface 24a of the tapered opening from the frictional force with the upper surface of the opening a.

Therefore, there is no possibility that the surplus cream solder 41b enters between the first mask 1a and the second mask 2a, and the reliability of the removal is increased. In addition,
Although described in the first step for convenience, the present invention can be similarly applied to the second step and is effective for removing excess cream solder.

Here, the substrate 3, the first mask 1a,
Detailed examples of the first mask 1b and the second masks 2a and 2b will be described with reference to FIG. First, FIG. 4A shows a plan view of the substrate 3. The substrate 3 has areas 4 and 5 for supplying cream solder. The region 4 is a region having a high mounting density composed of a plurality of regions with a narrow pitch on which a package such as a QFP is mounted, and it is desirable to supply thin low-temperature solder. The region 5 is a region where the electrical components such as capacitors are mounted at a relatively low mounting density, and the high-temperature solder may be supplied thickly. The direction of the solid arrow F indicates the sliding direction of the second masks 2a and 2b indicated by the solid arrows in FIGS. 1 and 2, and the areas 4 and 5 are on the same straight line parallel to this direction. Does not coexist.

Next, FIG. 4B shows a plan view of the first mask 1a. Openings 14 corresponding to each of regions 4 and 5
a and 15a. Further, through holes 16a, which are positioning means described later, are provided at the four corners, and the through holes 16a are slightly larger than the substrate 3 so that the through holes 16a do not overlap the substrate 3. In addition, this first mask 1a
The first mask 1 used in the first step of supplying the first cream solder and used in the second step
b has the same form as the first mask 1a except that the thickness is different, has openings 14b and 15b, and has a through hole 16b.

FIG. 4C is a plan view of the second mask 2a. It has an opening 24 corresponding to a part of the region 4 among the regions 4 and 5, and is used in the first step. Further, at the four corners, through holes 26a, which are positioning means to be described later, are provided so as to correspond to the respective through holes 16a, and are approximately the same size as the first masks 1a and 1b.

FIG. 4D shows the second mask 2b.
FIG. Of the regions 4 and 5, a region 5 different from the region 4 corresponding to the opening 24 of the second mask 2a.
, And is used in the second step. Further, at the four corners, through holes 26b, which are positioning means described later, are provided so as to correspond to the respective through holes 16a, and are approximately the same size as the first masks 1a and 1b.

The substrate 3, the first masks 1a, 1
b and the second masks 2a and 2b, the appropriate low-temperature solder (the first cream solder 4) is applied to the regions 4 and 5 on the substrate 3 by the cream solder supply method of the present invention.
1) and a high-temperature solder (second cream solder 42) are supplied. Then, if the heating temperature at the time of reflow is set to the high temperature side within the melting temperature range of the low-temperature solder, the high-temperature solder supplied to the area 5 sufficiently reflows, and the heat influence of the package and the like mounted in the area 4 The number of failures due to the above is significantly reduced.

By the way, in the screen printing, the positional deviation between each mask and the substrate in the plane direction is not preferable because it becomes impossible to supply cream solder to a desired region on the substrate. Therefore, in the third and fourth embodiments of the present invention described below, a positioning means is provided as a countermeasure against the positional deviation.

First, a third embodiment of the present invention will be described. FIGS. 5 and 6 show the positioning means in the first step of the third embodiment. The area of the substrate, the openings of the respective masks, the squeegee and the cream solder are not shown. The substrate 3 is held by the holding member 7, and the first mask 1a and the second mask 2a are sequentially stacked on the substrate 3. Here, the protrusions 6 provided on the holding member 7 and the through holes 16a, 26a provided at the four corners of each mask so as to correspond to the protrusions 6 are engaged. By this engagement,
Since the positions of each mask and the substrate are stable, it is possible to prevent a positional deviation in the planar direction when supplying the cream solder, and it is possible to secure the positional accuracy.

The protrusion 6 has a structure that can be moved in the through direction T of the through holes 16a and 26a by using a cylinder or the like. Then, at the time of supplying the cream solder, as shown in FIG. 6, the protrusion 6 is engaged with both the through holes 16a and 26a, so that the first mask 1a and the second mask 2
a is stable in the plane direction, but thereafter, the protrusion 6
Is moved in the through direction T to release the engagement with the through hole 26a of the second mask 2a, and the through hole 1 of the first mask 1a is released.
6a, the second mask 2a
Can be removed while sliding with respect to the first mask 1a.

Next, a fourth embodiment of the present invention will be described. 7 and 8 show the positioning means in the first step of the fourth embodiment. The area of the substrate, the openings of the respective masks, the squeegee and the cream solder are not shown. The feature of the fourth embodiment that is different from the third embodiment is that
Then, the convex portion 6 is fixed to the holding member 7, and the side surface of the through hole 26a of the second mask 2a on the side opposite to the sliding direction for removing the second mask 2a (indicated by a solid arrow) is formed. The notch 26c penetrates to the contour of the mask. Second, the convex portion 6 of the holding member 7, the second mask 2a
The notch 26c and the through hole 16a of the first mask 1a are provided in two of the four corners of each mask.

By forming the notch 26c in the through hole 26a as in the former, the notch 26c does not interfere with the protrusion 6 in the sliding direction (indicated by a solid line arrow), so that the protrusion 6 is fixed to the holding member 7. Thus, even if the second mask 2a is engaged with the second mask 2a, the second mask 2a can be removed in the sliding direction.

On the other hand, by providing the protrusion 6, the notch 26c, and the through hole 16a in at least two places as in the latter, the positions of each mask and the substrate can be stabilized. The second mask 2a is moved by a squeegee in a plane direction (indicated by a broken line arrow), which is a main factor causing a positional deviation,
Although it is loaded in the above direction, it is restrained by the side surface of the convex portion 6 and the notch 26c opposite to the above direction,
It does not shift.

The positioning means is not limited as long as the positions of each mask and the substrate are stable. For example,
A notch may be provided in the first mask, or a projection may be provided in the substrate. Further, the cross-sectional shape of the through-hole and the convex portion in the planar direction may be a polygon such as a triangle or a quadrangle, or other shapes. As in the embodiment, it is preferable that the cross-sectional shape is circular and the holding member is provided with a convex portion.

Although the third embodiment and the fourth embodiment have been described in the first step for convenience, the third embodiment and the fourth embodiment can be similarly applied to the second step. This is effective as a means for preventing the positional deviation.

[0058]

As described above, according to the present invention, there is provided a method for supplying cream solder to a plurality of regions on a substrate by screen printing provided with a mask and a squeegee. A first mask having:
A second part that right-clicks an opening corresponding to a part of the region;
The cream solder is supplied in such a manner that the mask solder is supplied in this order and the cream solder can be reliably supplied to a desired region on the same substrate.

After the cream solder has been supplied using the first mask and the second mask, only the second mask is removed from the substrate, and further, the first mask and the second And another second mask having an opening corresponding to a part of the region different from the region corresponding to the opening of the mask, in this order, by supplying the cream solder and a different type of cream solder, An appropriate type of cream solder having a constant thickness can be reliably supplied to a desired region on the same substrate.

After the cream solder is supplied using the first mask and the second mask, the first mask and the second mask are removed from the substrate, and another one thicker than the first mask is provided. A first mask, and the second
And another second mask having an opening corresponding to a part of the region different from the region corresponding to the opening of the mask, in this order, by supplying the cream solder and a different type of cream solder, It is possible to supply cream solders having different types as well as different thicknesses to desired regions on the same substrate.

When the second mask is removed in the plane direction while sliding the second mask with respect to the first mask after the cream solder is supplied, not only the excess cream solder can be reliably removed but also the formed cream solder can be removed. The thickness adjustment and accuracy control of the sheet are easy. Further, in the opening of the second mask, the side surface is inclined such that the cross-sectional shape on the opposite side to the sliding direction in which the second mask is removed is tapered in the search direction toward the sliding direction. This increases the certainty for removing excess cream solder.

Further, by forming the second mask in the form of a film, the amount of excess cream solder generated can be suppressed to a small amount, so that the amount to be removed can be reduced and the loss cost can be reduced.

Moreover, at least two projections provided on the holding member for holding the substrate and holes or notches provided on the first mask and the second mask so as to correspond to the projections, respectively. By the combination, the positions of each mask and the substrate are stabilized, so that it is possible to prevent positional displacement in the planar direction when supplying the cream solder, and it is possible to secure the positional accuracy of the supplied cream solder.

As a result, since the proper type of cream solder can be reliably supplied to the desired area on the same board, it is possible to select appropriate heating conditions at the time of reflow on the board, and to mount the mounted electric component after reflow. Reliability is also improved. In addition, since various types of lead-free solders having different characteristics can be effectively utilized, it can be expected as a method of preventing adverse effects on the natural environment, the human body, and the like.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first step in a cream solder supply method according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a second step in the cream solder supply method according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a cream solder supply method according to a second embodiment of the present invention.

FIG. 4 is a plan view showing a detailed example of a substrate, a first mask, and a second mask of the present invention.

FIG. 5 is a perspective view illustrating a cream solder supply method according to a third embodiment of the present invention.

6 is a sectional view taken along line AA of FIG.

FIG. 7 is a perspective view illustrating a cream solder supply method according to a fourth embodiment of the present invention.

FIG. 8 is a sectional view taken along the line BB of FIG. 7;

FIG. 9 is a cross-sectional view illustrating a conventional cream solder supply method.

[Explanation of symbols]

1a, 1a First mask 2a, 2b Second mask 3 Substrate 4, 5 Area 6 Convex part 7 Holding member 14a, 15a, 14b, 15b First mask opening 16a, 16b First mask through hole 24 , 25 second mask opening 26a, 26b second mask through hole 31, 32 squeegee 41, 42 cream solder t1a, t1b first mask thickness t2a, t2b second mask thickness

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B41F 15/36 B41F 15/36 Z A H05K 3/34 505 H05K 3/34 505C

Claims (9)

[Claims] 1. A method of supplying cream solder to a plurality of regions on a substrate by screen printing including a mask and a squeegee, wherein: a first mask having an opening corresponding to each of the regions; Having an opening corresponding to a part of the region
A cream solder supplying method, wherein the mask and the mask are stacked in this order and cream solder is supplied. 2. A method for supplying cream solder to a plurality of regions on a substrate by screen printing including a mask and a squeegee, wherein: a first mask having an opening corresponding to each of the regions; Having an opening corresponding to a part of the region
And the mask are supplied in this order, and cream solder is supplied. Then, only the second mask is removed from the substrate, and further, the first mask and the opening of the second mask in the region are further removed. Another second having an opening corresponding to a part of the region different from the corresponding region
And a mask solder different in type from the cream solder is supplied. 3. A method of supplying cream solder to a plurality of regions on a substrate by screen printing including a mask and a squeegee, wherein: a first mask having an opening corresponding to each of the regions; Having an opening corresponding to a part of the region
And a mask are supplied in this order, and cream solder is supplied. Thereafter, the first mask and the second mask are removed from the substrate, and further another first mask thicker than the first mask is provided. And another second mask having an opening corresponding to a part of the region different from the second mask, in this order, and supplying cream solder of a type different from the cream solder. A method for supplying cream solder, characterized in that: 4. The cream solder according to claim 1, wherein after the cream solder is supplied, the second mask is removed in a plane direction while sliding the second mask with respect to the first mask. Supply method. 5. The side face of the opening of the second mask is formed such that a cross-sectional shape of the opening opposite to the sliding direction in which the second mask is removed is tapered in the depth direction toward the sliding direction. 5. The cream solder supply method according to claim 4, wherein the cream solder is inclined. 6. The cream solder supply method according to claim 1, wherein the second mask has a film shape. 7. The cream solder supply method according to claim 1, wherein a positioning means for determining a position of the substrate, the first mask and the second mask in a planar direction is used. 8. The positioning means includes: at least two projections provided on a holding member for holding a substrate; and holes provided on the first mask and the second mask so as to correspond to the respective projections. 8. The method according to claim 7, wherein the notch engages with the notch. 9. The cream solder supply method according to claim 1, wherein the plurality of types of cream solder are lead-free solder.