JP2019155731A - Solder paste printing method, solder paste printing mask, and production method of electronic circuit module - Google Patents

Abstract

To provide a solder paste printing method that can prevent exudation of a solder paste even when irregularity exists on a printed wiring board and can stabilize a printing shape and a printing amount of the solder paste.SOLUTION: A printing method includes: a step of preparing a printed wiring board having a resist layer formed on a metal pattern layer; a mask arrangement step in which an opening is formed corresponding to an exposed surface area of the metal pattern layer and an irregular solder paste printing mask having a projected edge part of the opening is brought into contact with the printed wiring board; and a squeegeeing step of transferring the solder paste on the surface region of the metal pattern layer via the opening, in which the solder paste printing mask is positioned such that a projected part of the solder paste printing mask contacts with the edge part of the resist layer, and a recessed part of the solder paste printing mask comes into contact with the center part of the resist layer.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a solder paste printing method for printing a solder paste on a printed wiring board, a solder paste printing mask used therefor, and a method for manufacturing an electronic circuit module on which electronic components are mounted after the solder paste printing.

  A metal mask generally used for solder paste printing is designed so that an electronic component can be properly soldered for each printed wiring board, and an opening for printing the solder paste is provided at a desired position. Produced. Here, at the stage of designing the opening, the user who mounts the electronic component evaluates the opening for each component package, and accumulates information on the opening having the optimized shape. When a new printed wiring board is developed, information suitable for the electronic component to be mounted is extracted from the accumulated information and the mounting angle and the like are adjusted.

  When solder paste printing is performed using the metal mask, the metal mask is set in a printing machine, and the solder paste is discharged onto the metal mask. After that, with the printed wiring board in close contact with the back side of the metal mask, the solder paste is transferred onto the metal pad of the printed wiring board through the opening by pressing and sweeping a urethane or metal squeegee to Paste printing will be performed.

  In addition, as a general metal mask, a flat metal plate is used in consideration of mask deformation caused by pulling during squeegee pressurization and sweeping, and the periphery of the metal plate is fixed by a metal frame. ing. Furthermore, when a convex part exists in a printed wiring board, the recessed part which avoids a contact with the convex part of a printed wiring board is also formed in a metal mask. For example, Patent Document 1 discloses that a concave portion is formed on the metal mask side so that an overcoat resist formed so as to protrude from a circuit board is formed in a through hole portion.

Japanese Patent Laid-Open No. 06-206303

  In thick copper printed wiring boards for high-power modules, the patterned copper foil that becomes the wiring pattern and terminals is thicker than normal printed wiring boards, so the exposed copper foil is covered and protected. The resist layer to be thinned at the edge of the copper foil may expose the copper foil portion to be originally coated. In order to prevent such a problem, in the thick copper printed wiring board, a resist layer is formed thicker than a normal printed wiring board.

  However, in the thick copper printed wiring board, by making the resist layer thicker than a normal printed wiring board, the top portion of the resist layer and the copper foil portion (that is, the electronic component pad portion) on which the solder pace is printed. There may be a height difference of about 100 μm between them. In such a case, printing is performed in a state where the printed wiring board and the metal mask are not in close contact (that is, off-contact printing), and the solder paste oozes into the gap between the top of the resist layer and the electronic component pad. End up. For this reason, there is a problem in that the printed shape and printed amount of the solder paste are not stable, and the positional deviation of the mounted components and the quality defect such as the solder bridge occur.

  As a countermeasure against the poor quality, a method of reducing the printing pressure and a method of replacing the printing mask with a soft member such as a resin can be considered, but either method can obtain a countermeasure effect depending on the state of the printed wiring board and the printing conditions. It can be difficult. For this reason, the correspondence is a provisional measure, and the printed solder paste needs to be corrected.

  The present invention has been made in consideration of such circumstances, and the object of the present invention is to prevent the solder paste from leaking out even when the printed wiring board is uneven, An object of the present invention is to provide a solder paste printing method capable of stabilizing the printing shape and printing amount, a solder paste printing mask, and a method for manufacturing an electronic circuit module capable of further improving the mounting accuracy of electronic components.

  In order to achieve the above object, according to the solder paste printing method of the present invention, a resist layer whose thickness decreases from a central portion toward an edge portion is formed on a metal pattern layer, and a desired surface region of the metal pattern layer has a desired surface area. A preparatory step of preparing an exposed printed wiring board; and an uneven solder paste printing mask having an opening formed corresponding to the exposed surface region of the metal pattern layer and having an edge protruding from the opening. A mask arranging step for contacting the printed wiring board, a solder supplying step for supplying the solder paste onto the solder paste printing mask, and a squeegee slid on the solder paste printing mask, and through the opening A squeezing step of transferring a solder paste onto the surface region of the metal pattern layer, and in the mask placement step, the solder Positioning of the solder paste printing mask so that the convex portion of the first printing mask is in contact with the edge portion of the resist layer and the concave portion of the solder paste printing mask is in contact with the central portion of the resist layer Is made.

  In the solder paste printing method described above, in the mask arranging step, the solder paste printing mask may be positioned so that the outer edge of the convex portion is in contact with the edge portion of the resist layer.

  In any of the solder paste printing methods described above, in the mask arranging step, the solder paste printing mask is positioned so that the outer edge of the resist layer faces the convex portion of the solder paste printing mask. Also good.

  In any of the solder paste printing methods described above, in the mask arranging step, the solder paste printing mask is positioned so that the convex portion of the solder paste printing mask is separated from the metal pattern layer. Good.

  In the above-described solder paste printing method in which the convex portion of the solder paste printing mask is separated from the metal pattern layer, the separation amount of the convex portion with respect to the metal pattern layer is adjusted according to the average particle size of the solder paste. May be.

  In the above-described solder paste printing method in which the distance between the convex portion of the pad paste printing mask and the metal pattern layer is adjusted according to the average particle size of the solder paste, the separation amount of the convex portion with respect to the metal pattern layer is: The average particle size of the solder paste may be adjusted to 1.5 times or less.

  In order to achieve the above object, the solder paste printing mask according to the present embodiment has a resist layer formed on the metal pattern layer, the thickness of which decreases from the central portion toward the edge portion. A solder paste printing mask used in contact with the exposed printed wiring board, and a flat plate portion having an opening corresponding to the exposed surface area of the metal pattern layer; A protrusion protruding from the flat plate at the edge of the opening, and the height of the protrusion is smaller than the maximum layer thickness of the resist layer and is a dimension of a region surrounded by the outer edge of the protrusion Is larger than the size of the exposed surface region of the metal pattern layer, and the size of the opening is smaller than the size of the exposed surface region of the metal pattern layer.

  Furthermore, in order to achieve the above object, in the method of manufacturing an electronic circuit module according to the present embodiment, a resist layer whose thickness decreases from the center portion toward the edge portion is formed on the metal pattern layer, A preparation step of preparing a printed wiring board with a desired surface area exposed, and an uneven solder paste in which an opening is formed corresponding to the exposed surface area of the metal pattern layer and an edge of the opening protrudes A mask placement step of bringing a printing mask into contact with the printed wiring board, a solder supply step of supplying a solder paste onto the solder paste printing mask, and a squeegee sliding on the solder paste printing mask, A squeezing step of transferring the solder paste onto the surface region of the metal pattern layer through an opening; and the surface of the metal pattern layer A mounting step of mounting an electronic component on the solder paste transferred onto the area, and in the mask placement step, the convex portion of the solder paste printing mask contacts the edge of the resist layer. At the same time, the solder paste printing mask is positioned so that the concave portion of the solder paste printing mask is in contact with the central portion of the resist layer.

  The solder paste printing method and the metal mask according to the present invention can prevent the solder paste from bleeding even when the printed wiring board is uneven, and can stabilize the printed shape and the printing amount of the solder paste. it can. In addition, the electronic circuit module manufacturing method according to the present invention can further improve the mounting accuracy of electronic components.

It is a top view of the metal mask which concerns on a present Example. FIG. 2 is an enlarged cross-sectional view of the metal mask taken along the alternate long and short dash line II-II in FIG. 1. FIG. 3 is an enlarged cross-sectional view in the solder paste printing process shown in the same manner as in FIG. 2. FIG. 3 is an enlarged cross-sectional view in the solder paste printing process shown in the same manner as in FIG. 2. FIG. 3 is an enlarged cross-sectional view in the solder paste printing process shown in the same manner as in FIG. 2. FIG. 3 is an enlarged cross-sectional view in the solder paste printing process shown in the same manner as in FIG. 2. FIG. 3 is an enlarged cross-sectional view in the solder paste printing process shown in the same manner as in FIG. 2. It is a graph which shows the relationship of the transfer accuracy of the solder paste with respect to a metal mask, a printed wiring board, and a clearance gap.

  Hereinafter, a solder paste printing method, a metal mask, and an electronic circuit module manufacturing method according to an embodiment of the present invention will be described with reference to the drawings. In addition, this embodiment is not limited to the content demonstrated below, In the range which does not change the summary, it can change arbitrarily and can implement. In addition, the drawings used for the description of the embodiments all schematically show each member, and are partially emphasized, enlarged, reduced, or omitted to deepen the understanding. And may not accurately represent the shape or the like.

  FIG. 1 is a plan view of a metal mask according to the present embodiment. FIG. 2 is an enlarged cross-sectional view of the metal mask taken along one-dot chain line II-II in FIG.

  As shown in FIG. 1, a metal mask 10 according to the present embodiment is made of a relatively thin metal plate, and has a main body 10a in which a plurality of openings 11 for transferring solder paste are formed, and a main body 10a. It is comprised from the frame part 10b arrange | positioned so that an outer edge may be enclosed. In addition, since the metal mask 10 prints the solder paste in a state where the six printed wiring boards are juxtaposed and joined together (that is, not separated), the six printed wiring boards There is a region 12 (indicated by a broken line) corresponding to. That is, a region 12 surrounded by a broken line is a region corresponding to one printed wiring board.

  Here, the number of printed wiring boards that can be printed at a time described above is an example, and can be appropriately changed depending on the dimensions of the printed wiring board and the size of the printing machine on which the metal mask 10 is installed. Further, the size, shape, and quantity of the opening 11 can also be appropriately selected according to the target printed wiring board and the material and strength of the main body 10a.

  As shown in FIG. 2, the main body portion 10 a includes a flat plate portion 13 in which the opening 11 is formed and a protruding portion 14 that protrudes from the flat plate portion 13 at the edge of the opening 11. Here, the protrusion 14 is formed at each edge of all the openings 11 formed in the main body 10a. That is, the main body portion 10a has a concavo-convex shape including a convex portion that is the protruding portion 14 and a concave portion that is the flat plate portion 13 other than the convex portion.

  In the present embodiment, the thickness of the flat plate portion 13 is set to 40 μm, the height H1 of the protruding portion 14 is set to 40 μm, and the thickness W1 in the width direction of the protruding portion 14 is set to 150 μm by a design method of the metal mask 10 described later.

  Next, the solder paste printing method according to the present embodiment will be described with reference to FIGS. 3 to 7, and the positional relationship of each member when the metal mask 10 is brought into contact with the printed wiring board will be described in detail. explain. Here, FIGS. 3 to 7 are enlarged cross-sectional views in the solder paste printing process shown in the same manner as FIG.

  First, a printed wiring board 20 to be printed with solder paste is prepared (FIG. 3: preparation step). In the present embodiment, the printed wiring board 20 includes a base material 21 made of an insulating material, a metal pattern layer 22 made of copper formed on the base material 21, a resist layer 23 formed on the metal pattern layer 22, and a base A resist layer 24 formed on the material 21; The base material 21 may have a configuration in which a plurality of insulating layers are laminated, and may further have an internal wiring made of copper between the insulating layers. The metal pattern layer 22 corresponds to the land of the printed wiring board 20 and the external wiring pattern. The material of the metal pattern layer 22 is not limited to copper, and other metals such as gold and silver may be used.

  The resist layer 23 is formed so as to expose a desired surface region of the metal pattern layer 22 (that is, a portion that becomes a land). In addition, the resist layer 23 has a shape such that the thickness gradually decreases from the central portion toward the edge portion. Specifically, in the cross-sectional view shown in FIG. 3, the exposed surface of the resist layer 23 has an arcuate shape. The reason for this shape is that when the resist layer 23 is formed, the solder resist is applied by an ink jet method, and then the solder resist spreads. Therefore, the shape of the resist layer 23 results from the application amount of the solder resist, the application method, the surface tension, and the like.

  On the other hand, the resist layer 24 is formed so as to protect the exposed surface of the substrate 21. That is, the resist layer 24 is formed so as to fill the opening formed in the metal pattern layer 22 (that is, the gap exposing the base material 21).

  As described above, in the present embodiment, the printed wiring board 20 in which the entire surface is uneven due to the presence of the resist layer 23 is a target. In particular, in the case of a thick copper printed wiring board in which the metal pattern layer 22 is thick, the thickness of the resist layer 23 is also thick, and unevenness appears remarkably. Other configurations are not limited, and printed wiring boards having various configurations are targeted.

  Next, the concave-convex metal mask 10 shown in FIGS. 1 and 2 is brought into contact with the printed wiring board 20 from above to position the metal mask 10 (FIG. 4: mask placement step). Here, since the opening 11 of the metal mask 10 is formed corresponding to the exposed region of the metal pattern layer 22 (that is, the region not covered with the resist layer 23), the opening 11 of the metal pattern layer 22 is formed. Positioned on the exposed area. The positioning is performed by a position verification mechanism (not shown) using a recognition mark provided in a printing apparatus in which the metal mask 10 is installed.

  As shown in FIG. 4, the protrusion 14 positioned on the resist layer 23 side contacts the edge 23 a of the resist layer 23, and the flat plate portion 13 positioned above the resist layer 23 is the central portion of the resist layer 23. It is in contact with 23b. That is, the height H <b> 1 of the protrusion 14 is smaller than the maximum layer thickness of the resist layer 23. In particular, in the present embodiment, the metal mask 10 is positioned so that the outer edge 14a of the protrusion 14 contacts the edge 23a of the resist layer 23 and the outer edge 23c of the resist layer 23 faces the protrusion 14. ing. That is, the outer edge 23 c of the resist layer 23 is located in a region where the surface 14 b of the protruding portion 14 is projected onto the printed wiring board 20.

  On the other hand, the protrusion 14 of the metal mask 10 is completely separated from the metal pattern layer 22. In this embodiment, since the average particle size of the solder pace used is assumed to be about 32 μm (that is, the use of Typ4 solder paste is assumed), the distance L1 between the protrusion 14 and the metal pattern layer 22 ( That is, the separation amount is set to about 50 μm. The setting of the distance is adjusted according to the average particle size of the solder paste, but is preferably about 1.5 times or less the average particle size. The reason for this will be described in the description of the design method of the metal mask 10 described later.

  As described above, in the arrangement of the metal mask 10 according to the present embodiment, the contact of the metal mask 10 with the printed wiring board 20 is maintained by the contact between the flat plate portion 13 and the protruding portion 14 and the resist layer 23. Become. Therefore, in a situation where the printed wiring board 20 has irregularities, the metal mask 10 surrounds and contacts not only the upper surface of the resist layer 23 that becomes the convex portion of the printed wiring board 20 but also the side. Good contact of the metal mask 10 with the plate 20 is maintained, and good contact printing can be performed.

  Next, as shown in FIG. 5, a solder paste 30 is supplied onto the metal mask 10 (solder supply step). Subsequently, the squeegee 31 is slid in the direction of the arrow in FIG. 5 on the metal mask 10 to fill the opening 11 with the solder paste 30. As a result, the transfer of the solder paste is completed on the exposed surface region of the metal pattern layer 22, and the solder layer 33 is formed (FIG. 6: squeezing step). Here, although the transferred solder paste 30 has a gap between the protruding portion 14 and the metal pattern layer 22, the solder paste 30 exudes from the gap in consideration of the average particle size of the solder paste 30. Therefore, the shape of the solder layer 33 is not broken.

  In addition, the order of the solder supply process and the mask arrangement process described above may be reversed. That is, it is possible to supply the solder paste onto the metal mask 10 and then perform positioning and squeezing of the metal mask 10.

  The solder paste printing method according to this embodiment is completed through the above steps.

  Thereafter, the electronic component 40 is mounted on the solder layer 33 formed by the solder paste 30 transferred onto the surface region of the metal pattern layer 22 (FIG. 7: mounting process). Thereby, manufacture of the electronic circuit module 50 is completed, and the manufacturing process of the electronic circuit module according to the present embodiment is also completed.

  Next, a design method and a manufacturing method of the metal mask 10 will be described with reference to FIGS. 1, 2, 4, and 8. Here, FIG. 8 is a graph showing the relationship of the transfer accuracy of the solder paste to the metal mask, the printed wiring board, and the gap.

  First, the metal mask 10 corresponds to the type of the printed wiring board 20 to be printed, and the thickness, dimensions, and dimensions of the opening 11 are determined. Parameters important for forming the uneven shape are as follows. The next two. First, since the etching process is performed on the main body 10a of the metal mask 10 to form a concavo-convex shape, what percentage of etching can be performed with respect to the plate thickness before processing of the main body 10a. It is. This is influenced by the material of the main body 10a to be etched and the chemicals and apparatus used for the etching process. In this embodiment, it is assumed that about 50% of the etching process is possible with respect to the plate thickness before processing.

  Second, the thickness W1 of the protrusion 14 in the width direction can prevent deformation and breakage of the protrusion 14 in contact with the printed wiring board 20 when a standard printing pressure is applied to the metal mask 10. This is influenced by the material of the main body 10a, but in the present embodiment, it is assumed that a thickness of 0.15 mm or more is necessary.

  Next, when using the metal mask 10, the flat plate portion 13 contacts the central portion 23 b of the resist layer 23, and the outer edge 14 a of the protruding portion 14 contacts the edge portion 23 a of the resist layer 23. Since the shape of the resist layer 23 differs depending on the type of the printed wiring board 20 to be printed, the resist layer 23 that is a protruding portion of the printed wiring board 20 to be printed is measured. Specifically, the thickness of the central portion 23 b of the resist layer 23 and the portion located about 75 μm inside from the outer edge 23 c of the resist layer 23 is measured. Here, the numerical value of 75 μm is half of 150 μm, which is the minimum necessary value for the thickness W1 in the width direction of the protruding portion 14 in order to make the outer edge 14a of the protruding portion 14 face the central portion of the surface 14b of the protruding portion 14. Calculated as a value. In the present embodiment, the thickness of the central portion 23b of the resist layer 23 is about 90 μm, and the thickness of the portion located about 75 μm inside the outer edge 23c of the resist layer 23 is about 50 μm.

On the other hand, it is necessary to examine the bleeding of the solder paste 30 to be printed from the graph shown in FIG. In FIG. 8, the horizontal axis represents the gap size (μm), the vertical axis represents the transfer accuracy, and a graph relating to the solder paste 30 having an average particle diameter of 32 μm is shown. Here, the transfer accuracy is calculated from the following equation.
(Formula 1)
Transfer accuracy = (volume of solder paste 30 transferred) / “(opening area of opening 11 of metal mask 10) × (thickness of flat plate portion 13 + thickness of protruding portion 14)”

  As shown in FIG. 8, in the solder paste 30 having an average particle diameter of 32 μm, it can be seen that the solder paste 30 oozes out when the size of the gap exceeds 40 μm. In addition, when the gap size is 50 μm, the amount of seepage is relatively small and no significant reduction in transfer accuracy is observed. However, when the size of the gap exceeds 60 μm, the amount of seepage becomes relatively large and the transfer accuracy is increased. There is a significant decrease in That is, in the solder paste 30 having an average particle diameter of 32 μm, setting the gap size to 50 μm or less leads to improvement in transfer accuracy. In other words, the size of the gap is preferably 1.5 times or less of the average particle size.

  For solder pastes having other average particle diameters, the graph shown in FIG. 8 only slides in the horizontal axis direction, and the relationship between the gap and the transfer accuracy is almost the same. That is, even in a solder paste having another average particle size, it is preferable that the size of the gap be 1.5 times or less of the average particle size.

  In the present embodiment, since the thickness of the portion located about 75 μm inside the outer edge 23c of the resist layer 23 is about 50 μm, the metal mask 10 protrudes into the portion located about 75 μm inside from the outer edge 23c of the resist layer 23. If the outer edge 14a of the portion 14 is brought into contact, it can be understood that the distance L1 (that is, the distance) between the protruding portion 14 and the metal pattern layer 22 can be adjusted within a range in which the transfer accuracy does not decrease.

  Here, the protrusion 14 and the metal pattern layer 22 are brought into contact with each other and the separation amount is set to zero, so that excellent transfer accuracy can be realized, but the length of the opening 11 (thickness of the flat plate portion 13 + protrusion) Since the thickness of the portion 14 is increased, the print omission is deteriorated. Accordingly, in consideration of printing omission, it is preferable that the distance between the protruding portion 14 and the metal pattern layer 22 is large. However, if the size is too large, the solder paste 30 oozes out, so that the thickness of the metal plate serving as the material of the main body 10a It is more preferable to determine an appropriate distance in consideration of the etching amount and the average particle size of the solder paste.

  Then, the above-mentioned parameters are taken into the design matters, and the metal plate as the material of the main body 10a is taken into consideration in consideration of the size, shape, and quantity of the land of the printed wiring board 20 (exposed region of the metal pattern layer 22). Etching is performed. Thereby, the uneven main body 10a is created, and then the metal mask 10 is completed by attaching the frame body 10b to the outer edge of the main body 10a.

  When solder paste printing is performed using the metal mask 10 completed by the design method described above, the protrusion 14 of the metal mask 10 contacts the edge 23a of the resist layer 23, and the flat plate portion 10a of the metal mask 10 The solder paste 30 can be printed while contacting the central portion 23b of the resist layer 23 and maintaining excellent contact. In particular, in the present embodiment, the metal mask 10 is positioned so that the outer edge 14 a of the protrusion 14 contacts the edge 23 a of the resist layer 23 and the outer edge 23 c of the resist layer 23 faces the protrusion 14. This makes it possible to further improve the transfer accuracy of the solder paste 30.

  Further, when the solder paste is printed, the protruding portion 14 and the metal pattern layer 22 are separated from each other, so that the printing omission can be improved, and the separation amount is 1.5 times the average particle size of the solder paste 30. Therefore, the solder paste 30 can be prevented from seeping out.

  If solder paste printing or manufacturing of an electronic circuit module is performed using the metal mask 10, the solder paste 30 can be prevented from seeping out even when the printed wiring board 20 is uneven. The printing shape and printing amount can be stabilized.

10 Metal mask (mask for solder paste printing)
DESCRIPTION OF SYMBOLS 10a Main body part 10b Frame part 11 Opening 12 Area | region corresponding to one printed wiring board 13 Flat plate part (recessed part)
14 Protruding part (convex part)
14a outer edge 14b surface 20 printed wiring board 21 substrate 22 metal pattern layer 23 resist layer 23a edge 23b center 23c outer edge 24 resist layer 30 solder paste 31 squeegee 33 solder layer 40 electronic component 50 electronic circuit module

Claims (8)

A preparatory step of preparing a printed wiring board in which a resist layer whose thickness decreases from the center toward the edge is formed on the metal pattern layer, and a desired surface region of the metal pattern layer is exposed;
A mask placement step in which an opening is formed corresponding to the exposed surface region of the metal pattern layer, and an uneven solder paste printing mask in which an edge of the opening protrudes contacts the printed wiring board;
A solder supplying step of supplying a solder paste onto the solder paste printing mask;
A squeegee step for sliding a squeegee on the solder paste printing mask and transferring the solder paste onto the surface region of the metal pattern layer through the opening,
In the mask arranging step, the convex portion of the solder paste printing mask is in contact with the edge portion of the resist layer, and the concave portion of the solder paste printing mask is in contact with the central portion of the resist layer. The solder paste printing method, wherein the solder paste printing mask is positioned.   2. The solder paste printing method according to claim 1, wherein in the mask arranging step, the solder paste printing mask is positioned so that an outer edge of the convex portion is in contact with the edge portion of the resist layer.   3. The solder paste according to claim 1, wherein in the mask arranging step, the solder paste printing mask is positioned such that an outer edge of the resist layer faces the convex portion of the solder paste printing mask. Printing method.   4. The solder paste printing mask according to claim 1, wherein in the mask arranging step, the solder paste printing mask is positioned so that the convex portion of the solder paste printing mask is separated from the metal pattern layer. 5. The solder paste printing method as described.   5. The solder paste printing method according to claim 4, wherein a distance between the protrusions with respect to the metal pattern layer is adjusted according to an average particle diameter of the solder paste.   The solder paste printing method according to claim 5, wherein a distance between the protrusions with respect to the metal pattern layer is 1.5 times or less of an average particle diameter of the solder paste. Solder paste printing is used in which a resist layer whose thickness decreases from the center toward the edge is formed on the metal pattern layer, and is used in contact with a printed wiring board on which a desired surface area of the metal pattern layer is exposed. Mask for
A flat plate portion having an opening formed corresponding to the exposed surface region of the metal pattern layer;
And a protruding portion protruding from the flat plate portion at the edge of the opening,
The height of the protrusion is smaller than the maximum layer thickness of the resist layer,
The size of the region surrounded by the outer edge of the protrusion is larger than the size of the exposed surface region of the metal pattern layer,
The solder paste printing mask is such that the size of the opening is smaller than the size of the exposed surface region of the metal pattern layer. A preparatory step of preparing a printed wiring board in which a resist layer whose thickness decreases from the center toward the edge is formed on the metal pattern layer, and a desired surface region of the metal pattern layer is exposed;
A mask placement step in which an opening is formed corresponding to the exposed surface region of the metal pattern layer, and an uneven solder paste printing mask in which an edge of the opening protrudes contacts the printed wiring board;
A solder supplying step of supplying a solder paste onto the solder paste printing mask;
A squeegee step for sliding a squeegee on the solder paste printing mask and transferring the solder paste onto the surface region of the metal pattern layer through the opening;
A mounting step of mounting an electronic component on the solder paste transferred onto the surface region of the metal pattern layer,
In the mask arranging step, the convex portion of the solder paste printing mask is in contact with the edge portion of the resist layer, and the concave portion of the solder paste printing mask is in contact with the central portion of the resist layer. A method of manufacturing an electronic circuit module, wherein the solder paste printing mask is positioned.

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