Mask for mounting conductive material and method for manufacturing the same

Abstract

A mask (4) for mounting a conductive substance is provided with a first plating layer (10) and a second plating layer (20). The first plating layer (10) includes a flat surface (10b) and is formed continuously without being divided into a plurality of portions. The second plating layer (20) covers the first plating layer (10) from the surface (10b) side, and is formed continuously without being divided into a plurality of portions. A conductive substance supply surface (4a) is formed by the first plating layer (10) and a thin plate formation part. A plurality of opening patterns (6) is formed in the thin plate formation part.

Description

[Technical Field]

[0001] The present disclosure relates to a conductive material mounting mask used for mounting a conductive material such as a solder ball or a copper pillar on an object to be mounted, and a method for manufacturing the conductive material mounting mask. [Background technology]

[0002] A ball mounting mask is described in Patent Document 1. The ball mounting mask described in Patent Document 1 is manufactured by the following procedure.

[0003] First, a primary plating layer is formed on the base material. Next, the primary residual plating portion of the primary plating layer is left, and the primary sacrificial plating portion is peeled off from the base material. Multiple separate and independent primary residual plating portions remain on the base material. After that, a secondary plating layer is formed on the base material and the primary residual plating portion. Holes through which the conductive balls pass are formed in the secondary plating layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2022 / 045073 Summary of the Invention [Problem to be solved by the invention]

[0005] The ball mounting mask described in Patent Document 1 has multiple separate and independent primary residual plating portions. As a result, the bonding area between each of the primary residual plating portions and the secondary plating layer is small, which causes a problem that the primary residual plating portions tend to peel off from the secondary plating layer during cleaning, for example.

[0006] The present disclosure has been made to solve the above-mentioned problems. An object of the present disclosure is to provide a mask for mounting a conductive material that can suppress peeling of a plating layer. Another object of the present disclosure is to provide a method for manufacturing such a mask for mounting a conductive material. [Means for solving the problem]

[0007] The conductive material mounting mask according to the present disclosure comprises a first plating layer having a flat first surface and formed as a single continuous layer without being divided into multiple pieces, and a second plating layer covering the first plating layer from the first surface side and formed as a single continuous layer without being divided into multiple pieces. A flat conductive material supply surface onto which the conductive material is supplied is formed by the first plating layer and a thin plate forming portion of the second plating layer that does not overlap with the first plating layer. The distance between the second surface of the thin plate forming portion and the conductive material supply surface is smaller than the distance between a third surface of the thick plate forming portion of the second plating layer that overlaps with the first plating layer and the conductive material supply surface. The second surface and the third surface face in the same direction as the first surface. A plurality of opening patterns are formed in the thin plate forming portion. Each of the plurality of opening patterns includes a plurality of through holes for allowing the conductive material to pass through.

[0008] The method for manufacturing a mask for mounting a conductive material according to the present disclosure includes a first step of forming a first resist on a base material so as to outline an area corresponding to a portion of the conductive material supply surface formed by a thin plate forming portion, a second step of plating the base material after the first step, a third step of removing the first resist after the second step, a fourth step of peeling off the plating formed in the area to leave a first plating layer on the base material after the second step, a fifth step of forming a second resist in an area of ​​the base material corresponding to the plurality of through holes after the third and fourth steps, and a sixth step of plating the first plating layer and the area of ​​the base material after the fifth step to form a second plating layer. [Effects of the Invention]

[0009] The mask for applying a conductive material according to the present disclosure can prevent the plating layer from peeling off. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing an example of a plate provided with a conductive material application mask according to the first embodiment. FIG. [Figure 2] FIG. 2 is a diagram showing a cross section of the plate shown in FIG. [Figure 3] 10A and 10B are diagrams showing examples of a mask for applying a conductive material. [Figure 4] 10A and 10B are diagrams showing examples of a mask for applying a conductive material. [Figure 5] FIG. 5 is a view showing a cross section CC of FIG. [Figure 6] FIG. 6 is an enlarged view of part D shown in FIG. 5. [Figure 7] FIG. 5 is a view showing an E-E cross section of FIG. [Figure 8] FIG. 2 is a diagram showing an example of a first plating layer. [Figure 9] 1 is a flowchart showing an example of a method for manufacturing a mask for applying a conductive material according to the first embodiment. [Figure 10] 10A to 10C are diagrams for explaining a method for manufacturing a mask for applying a conductive material. [Figure 11] 10A to 10C are diagrams for explaining a method for manufacturing a mask for applying a conductive material. [Figure 12] FIG. 2 is a diagram showing an example of a first resist formed on a base material in a first step. [Figure 13] 10A and 10B are diagrams showing other examples of the mask for applying a conductive material. [Figure 14] 10A and 10B are diagrams showing other examples of the mask for applying a conductive material. [Figure 15] 10A to 10C are diagrams illustrating a step of forming a protrusion. DETAILED DESCRIPTION OF THE INVENTION

[0011] The following detailed description will be given with reference to the drawings. Duplicate descriptions will be simplified or omitted as appropriate. In each drawing, the same reference numerals indicate the same or corresponding parts.

[0012] Embodiment 1 FIG. 1 is a diagram showing an example of a plate 1 provided with a mask 4 for mounting a conductive substance in the first embodiment. FIG. 2 is a diagram showing a cross section of the plate 1 shown in FIG. 1. The plate 1 includes a frame 2, a mesh 3, and a mask 4 for mounting a conductive substance. The mask 4 for mounting a conductive substance is attached to the frame 2 via the mesh 3. The mesh 3 is arranged around the mask 4 for mounting a conductive substance. The mesh 3 applies tension to the mask 4 for mounting a conductive substance.

[0013] The conductive material mounting mask 4 is used to mount a solid conductive material such as a solder ball or a copper pillar onto an object to be mounted. The object to be mounted is, for example, a substrate 5. When the conductive material is to be mounted onto the object, the conductive material mounting mask 4 is placed above the object.

[0014] A large number of conductive materials are supplied to the conductive material supply surface 4a of the conductive material mounting mask 4. The conductive material supply surface 4a is flat. In the example shown in FIGS. 1 and 2, the conductive material supply surface 4a faces upward. The conductive materials supplied to the conductive material supply surface 4a pass through the conductive material mounting mask 4 and are mounted at appropriate positions on the object to be mounted.

[0015] 3 and 4 are diagrams showing examples of the conductive material mounting mask 4. FIG. 3 is a diagram showing the conductive material mounting mask 4 as viewed from the direction B in FIG. 2. FIG. 3 shows the surface facing the object to be mounted. Hereinafter, this surface will also be referred to as the facing surface. FIG. 4 is a diagram showing the conductive material mounting mask 4 as viewed from the direction A in FIG. 2. FIG. 4 shows the conductive material supply surface 4a. FIG. 5 is a diagram showing a CC cross section of FIG. 4. FIG. 6 is an enlarged view of part D shown in FIG. 5. FIG. 7 is a diagram showing an EE cross section of FIG. 4. Note that FIG. 2 shows a cross section corresponding to FIG. 5.

[0016] A plurality of opening patterns 6 are provided in the mask 4 for applying a conductive material. FIGS. 3 and 4 show an example in which the opening patterns 6 are regularly arranged in four columns and three rows. The arrangement of the opening patterns 6 is set arbitrarily. Each of the plurality of opening patterns 6 includes a plurality of through holes 7 for passing the conductive material. The arrangement of the through holes 7 included in each opening pattern 6 may all be the same.

[0017] The conductive material mounting mask 4 includes a first plating layer 10 and a second plating layer 20. The first plating layer 10 is formed by a plating method. FIG. 8 is a diagram showing an example of the first plating layer 10. FIG. 8 shows only the first plating layer 10 in FIG. 4.

[0018] The first plating layer 10 is plate-shaped and formed in one continuous piece without being divided into multiple pieces. The first plating layer 10 has a surface 10a and a surface 10b. The surfaces 10a and 10b are flat. The surface 10a faces upward when the conductive material mounting mask 4 is placed on the object to be mounted. The surface 10a is part of the conductive material supply surface 4a. The surface 10b faces in the opposite direction to the surface 10a. The surface 10b faces downward when the conductive material mounting mask 4 is placed on the object to be mounted.

[0019] The entire edge of the conductive material supply surface 4a is preferably formed by the first plating layer 10. Furthermore, it is preferable that the first plating layer 10 is present between each two adjacent opening patterns 6 among the plurality of opening patterns 6 provided in the mask 4 for applying a conductive material. For example, a portion of the first plating layer 10 designated by reference numeral 10c is present between opening pattern 6a and opening pattern 6b. A portion of the first plating layer 10 designated by reference numeral 10d is present between opening pattern 6a and opening pattern 6c. The opening pattern 6a, opening pattern 6b, and opening pattern 6c are each one of the plurality of opening patterns 6 provided in the mask 4 for applying a conductive material.

[0020] It is not essential that the first plating layer 10 exists between each pair of adjacent opening patterns 6. For example, in the example shown in Fig. 4, the first plating layer 10 does not have to exist between the four opening patterns 6 in the upper row. However, it is preferable that the first plating layer 10 exists between each opening pattern 6 and any other opening pattern adjacent to it on either the top, bottom, left, or right.

[0021] The second plating layer 20 is formed by a plating method. The second plating layer 20 is provided so as to cover the first plating layer 10 from the surface 10b side. For example, the second plating layer 20 covers the entire first plating layer 10 from the surface 10b side. The second plating layer 20 is formed as a single piece without being divided into multiple parts.

[0022] The second plating layer 20 includes a portion that overlaps with the first plating layer 10 and a portion that does not overlap with the first plating layer 10. The thickness of the mask 4 for mounting a conductive material at the portion where the second plating layer 20 overlaps with the first plating layer 10 is greater than the thickness at the portion where the second plating layer 20 does not overlap with the first plating layer 10. Hereinafter, the portion of the second plating layer 20 that overlaps with the first plating layer 10 will also be referred to as the thick plate forming portion. The portion of the second plating layer 20 that does not overlap with the first plating layer 10 will also be referred to as the thin plate forming portion. It is preferable that the thin plate forming portion be composed of only the second plating layer 20.

[0023] The second plating layer 20 has a surface 20a. The surface 20a is the surface of the thin plate forming portion, and is the surface that faces upward when the conductive material mounting mask 4 is placed on the mounting object. The surface 20a is part of the conductive material supply surface 4a. In other words, the surface 20a faces in the same direction as the surface 10a faces. The surfaces 20a and 10a form the same plane.

[0024] In the example shown in this embodiment, the area of ​​the conductive material supplying surface 4a other than the surface 10a is the surface 20a. The conductive material supplying surface 4a is formed by the first plating layer 10 and the thin plate forming portion of the second plating layer 20. FIG. 4 shows the most preferable example in which the area of ​​the conductive material supplying surface 4a formed by the thin plate forming portion is continuous without being divided into multiple parts. This is just one example. The area may be divided into multiple parts. For example, if the area is divided into multiple parts, it is preferable that at least one of the divisions includes multiple opening patterns 6. It is even more preferable that each of the divisions includes multiple opening patterns 6.

[0025] The opposing surface of the conductive material mounting mask 4 is formed by the second plating layer 20. As described above, the second plating layer 20 includes a thick plate forming portion and a thin plate forming portion. Furthermore, the surface 20a of the thin plate forming portion is flush with the surface 10a of the first plating 10. Therefore, the second plating layer 20 is not completely flat, and the opposing surface has irregularities.

[0026] The distance L1 between the conductive material supply surface 4a and the surface 20b of the thin plate forming portion is smaller than the distance L2 between the conductive material supply surface 4a and the surface 20c of the thick plate forming portion. The surface 20b is the surface of the thin plate forming portion, and is the surface that faces downward when the conductive material mounting mask 4 is placed on the object to be mounted. The surface 20b is part of the opposing surface. The surface 20c is the surface of the thick plate forming portion, and is the surface that faces downward when the conductive material mounting mask 4 is placed on the object to be mounted. The surface 20c is part of the opposing surface. The surfaces 20b and 20c face in the same direction as the surface 10b.

[0027] As shown in Figures 5 to 7, the thick plate forming portion of the opposing surface of the mask 4 for mounting a conductive material is convex. In other words, the thin plate forming portion is concave. In this way, a recess is formed by the thin plate forming portion on the opposing surface of the mask 4 for mounting a conductive material. The recess formed by the thin plate forming portion on the opposing surface of the mask 4 for mounting a conductive material includes a recess 8a in which the opening pattern 6 is formed and a groove-like recess 8b extending from the recess 8a.

[0028] Each opening pattern 6 is formed in the thin plate forming portion. For example, a recess 8b connects two recesses 8a in which an opening pattern 6 is formed. Fig. 3 shows a preferred example in which one opening pattern 6 is formed in one recess 8a and all the recesses 8a are connected by the recesses 8b.

[0029] Next, a method for manufacturing the mask 4 for mounting a conductive material will be described with reference to Fig. 9 to Fig. 12. Fig. 9 is a flowchart showing an example of a method for manufacturing the mask 4 for mounting a conductive material in the first embodiment. Fig. 10 and Fig. 11 are diagrams for explaining the method for manufacturing the mask 4 for mounting a conductive material.

[0030] First, in S101, a first step is performed in which a first resist 31 is formed on a base material 30. In this embodiment, resist is an example of a photosensitive material. In the first step, a conductive base material 30 is first prepared as shown in FIG. 10(a). Next, a layer of resist is formed on the surface 30a of the base material 30, followed by exposure and development. As a result, a first resist 31 is formed on the surface 30a of the base material 30 so as to outline a region corresponding to the portion of the conductive material supply surface 4a formed by the thin plate forming portion. Hereinafter, this region on the surface 30a will be referred to as region F.

[0031] FIG. 12 is a diagram showing an example of a first resist 31 formed on the base material 30 in the first step. FIG. 12 is a diagram showing the surface 30a of the base material 30 as viewed from above. As described above, in the example shown in this embodiment, the portion of the conductive material supply surface 4a formed by the thin plate forming portion is continuous without being divided into multiple parts. Therefore, the first resist 31 is formed endlessly so that it can be drawn in one stroke when viewing the surface 30a from above. Each cross section shown in FIGS. 10 and 11 shows a cross section corresponding to the GG cross section in FIG. 12. By performing the first step, the first resist 31 is formed on the surface 30a of the base material 30 as shown in FIG. 10(b).

[0032] After the first step, a second step S102 is performed in which primary plating is performed on the surface 30a of the base material 30. For example, electroforming or electroless plating is used for the primary plating. As a result, a plating layer is formed on the surface 30a in an area surrounded by the first resist 31 and in an area other than the area surrounded by the first resist 31. In the following, the plating layer formed in the area surrounded by the first resist 31 is denoted by the symbol J1. The plating layer formed in the area other than the area surrounded by the first resist 31 is denoted by the symbol J2. By performing the second step, the base material 30 is plated, and as shown in FIG. 10(c), plating layers J1 and J2 are formed on the surface 30a.

[0033] After the second step, in S103, a third step is performed to remove the first resist 31. In the third step, a stripping solution is used to remove the first resist 31. As a result, the first resist 31 is removed from the base material 30, as shown in FIG. 10(d).

[0034] After the third step, in S104, a fourth step is performed in which the plating formed in the region F is stripped off. That is, in the fourth step, the plating layer J1 is removed from the base material 30. As a result, as shown in FIG. 10(e), the plating layer J2 remains on the surface 30a of the base material 30. The first plating layer 10 is the plating layer J2 that is not stripped off from the base material 30 in the fourth step and remains on the surface 30a.

[0035] The order of the third and fourth steps may be reversed. For example, the fourth step may be performed immediately after the second step, and the third step may be performed after the fourth step.

[0036] After the third and fourth steps, in S105, a fifth step is performed in which a second resist 32 is formed in region F of the base material 30. The second resist 32 is a resist that corresponds to the plurality of through holes 7 included in each opening pattern 6. That is, the second resist 32 is provided at a position where the through holes 7 will be formed. In the fifth step, after the resist is formed in region F, exposure and development are performed. As a result, the second resist 32 is formed on the surface 30a of the base material 30, as shown in FIG. 11(a).

[0037] After the fifth step, in S106, a sixth step is performed in which secondary plating is performed on the plating layer J2 (first plating layer 10) and region F of the base material 30. For the secondary plating, for example, electroforming or electroless plating is used. As a result, a plating layer is formed on the plating layer J2 and region F, as shown in FIG. 11(b). The plating layer formed in the sixth step is the second plating layer 20.

[0038] After the sixth step, in S107, a seventh step is performed in which the second resist 32 is removed. In the seventh step, a stripping solution is used to remove the second resist 32. By removing the second resist 32, holes are formed in the second plating layer 20, as shown in FIG. 11(c). The holes formed in the second plating layer 20 in the seventh step are through holes 7.

[0039] Finally, in S108, an eighth step is performed in which the plating layer J2 (first plating layer 10) and the second plating layer 20 are separated integrally from the base material 30. This makes it possible to obtain a mask 4 for applying a conductive material as shown in Figures 3 to 7. Furthermore, by attaching the mask 4 for applying a conductive material to a frame 2 via a gauze 3, the plate 1 as shown in Figures 1 and 2 is completed.

[0040] In the conductive material mounting mask 4, the first plating layer 10 is formed as a single piece without being divided into multiple pieces. This allows a large bonding area between the first plating layer 10 and the second plating layer 20, and prevents the first plating layer 10 from peeling off.

[0041] In the conductive material loading mask 4, it is preferable that the region formed by the thin plate forming portion on the conductive material supply surface 4a is continuous and not divided into multiple parts. This can be achieved by forming the first resist 31 in the first step so that the region F is continuous and not divided into multiple parts. In this example, it is possible to remove only one plating film in the fourth step, minimizing the removal step and improving work efficiency.

[0042] In the mask 4 for depositing a conductive material, it is preferable that the first plating layer 10 is present between each two adjacent opening patterns 6 among the plurality of opening patterns 6 provided in the mask 4 for depositing a conductive material. Such a configuration can be realized by appropriately setting the formation position of the first resist 31 in the first step and the formation position of the second resist 32 in the fifth step. In this example, a thick portion with increased strength can be disposed between each opening pattern 6.

[0043] The following describes other functions that can be adopted by the conductive material applying mask 4. If possible, the conductive material applying mask 4 may adopt a combination of the following functions.

[0044] FIG. 13 is a diagram showing another example of the conductive material mounting mask 4. FIG. 13 is a diagram showing the conductive material mounting mask 4 as viewed from the direction A in FIG. 2 and corresponds to FIG. 4. The conductive material mounting mask 4 shown in FIG. 13 differs from the conductive material mounting mask 4 shown in FIG. 4 in that only one region of the conductive material supplying surface 4a formed by the thin plate forming portion reaches the edge of the conductive material supplying surface 4a. That is, in the example shown in FIG. 13, one recess 8b reaches the edge of the opposing surface. In this example, when the plating layer J1 is peeled off in the fourth step, the plating layer J1 can be peeled off all at once from the areas not surrounded by the plating layer J2, thereby improving the efficiency of the work.

[0045] Fig. 14 is a diagram showing another example of the mask 4 for depositing a conductive material. Fig. 14 is a cross-sectional view corresponding to Fig. 6, and is an enlarged view of part D shown in Fig. 5. The mask 4 for depositing a conductive material shown in Fig. 14 differs from the mask 4 for depositing a conductive material shown in Fig. 6 in that it further includes protrusions 11. The protrusions 11 protrude from the end face of the first plating layer 10 into the thin plate forming portion of the second plating layer 20. Fig. 14 shows an example in which the first plating layer 10 and the protrusions 11 are formed integrally.

[0046] FIG. 15 is a diagram illustrating the process of forming the protrusions 11. FIG. 15(a) corresponds to FIG. 10(c), and FIG. 15(b) corresponds to FIG. 11(c). When the protrusions 11 are to protrude from the end face of the first plating layer 10, for example, a plating layer having a thickness greater than that of the first resist 31 is formed in the second process. When the thickness of the plating on the base material 30 exceeds that of the first resist 31, the plating also grows horizontally from the portion exceeding the thickness of the first resist 31. This allows the protruding portion of the plating formed in the second process that has grown horizontally on the first resist 31 to be used as the protrusion 11.

[0047] 15(b), the secondary plating is performed so that the protruding portions are completely hidden. In this example, the protrusions 11 can be made hook-shaped, which further prevents the first plating layer 10 from peeling off from the second plating layer 20. Note that the shape of the protrusions 11 is not limited to a hook shape. [Industrial Applicability]

[0048] The mask according to the present disclosure can be used for mounting a conductive material. [Explanation of symbols]

[0049] 1 plate, 2 frame, 3 gauze, 4 conductive material mounting mask, 4a conductive material supply surface, 5 substrate, 6 opening pattern, 7 through hole, 8a-8b recess, 10 first plating layer, 10a surface, 10b surface, 11 protrusion, 20 second plating layer, 20a-20c surfaces, 30 base material, 30a surface, 31 first resist, 32 second resist

Claims

1. a first plating layer having a flat first surface and formed continuously without being divided into a plurality of parts; a second plating layer that covers the first plating layer from the first surface side and is formed continuously without being divided into multiple layers; Equipped with a flat conductive material supply surface onto which a conductive material is supplied is formed by the first plating layer and a thin plate forming portion of the second plating layer that does not overlap with the first plating layer; a distance between a second surface of the thin plate forming portion and the conductive material supply surface is smaller than a distance between a third surface of the thick plate forming portion that overlaps the first plating layer of the second plating layer and the conductive material supply surface; the second surface and the third surface face in the same direction as the first surface; A plurality of opening patterns are formed in the thin plate forming portion, The conductive material loading mask has a plurality of through holes for passing a conductive material through each of the plurality of opening patterns.

2. 2. The mask for mounting a conductive material according to claim 1, wherein the area of ​​the conductive material supply surface formed by the thin plate forming portion is continuous without being divided into a plurality of parts.

3. 3. The conductive material loading mask according to claim 2, wherein said region reaches an edge of said conductive material supplying surface at only one point.

4. 4. The mask for mounting a conductive material according to claim 1, wherein the first plating layer is present between each pair of adjacent opening patterns among the plurality of opening patterns.

5. 4. The mask for mounting a conductive material according to claim 1, further comprising a protrusion protruding from an end face of the first plating layer into the thin plate forming portion.

6. A method for manufacturing the conductive material mounting mask according to claim 1, comprising: a first step of forming a first resist on a base material so as to border a region corresponding to a portion of the conductive material supply surface formed by the thin plate forming portion; a second step of plating the base material after the first step; a third step of removing the first resist after the second step; a fourth step of removing the plating formed in the region after the second step, thereby leaving the first plating layer on the base material; a fifth step of forming a second resist corresponding to the plurality of through holes in the region of the base material after the third step and the fourth step; a sixth step of plating the first plating layer and the region of the base material after the fifth step to form the second plating layer; A method for manufacturing a mask for mounting a conductive material, comprising:

7. 7. The method for manufacturing a mask for mounting a conductive material according to claim 6, wherein in the first step, the first resist is formed so that the region is continuous without being divided into a plurality of regions.

8. 8. The method for manufacturing a mask for mounting a conductive material according to claim 6, wherein the first resist is formed in the first step, and the second resist is formed in the fifth step, so that the first plating layer is present between each two adjacent opening patterns among the plurality of opening patterns.

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