Mask for mounting conductive substance and method for producing mask for mounting conductive substance

Abstract

A mask (4) for mounting a conductive substance is provided with a first plating layer (10) and a second plating layer (20). The second plating layer (20) covers the first plating layer (10) from one surface side thereof, and is formed continuously without being divided into a plurality of portions. The first plating layer (10) is provided with a reinforcing part (11) and a plurality of post parts (12). The reinforcing part (11) is disposed so as to surround the periphery of a plurality of opening patterns (6). The plurality of post parts (12) are arranged so as to surround each of the plurality of opening patterns (6).

Description

Mask for mounting conductive material and method for manufacturing the same

[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.

[0002] A ball array mask is described in Patent Document 1. The ball array mask described in Patent Document 1 includes a mask body having openings formed therein and protrusions provided on the mask body.

[0003] Japanese Patent Application Publication No. 2017-5053

[0004] In the ball array mask described in Patent Document 1, protrusions are provided near the openings through which the conductive balls pass. That is, the majority of the ball array mask is formed only by the mask body. For this reason, there are problems in that the ball array mask has low durability and is prone to elongation after long-term use.

[0005] 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 is excellent in durability. Another object of the present disclosure is to provide a method for manufacturing such a mask for mounting a conductive material.

[0006] The conductive material mounting mask according to the present disclosure comprises a first plating layer and a second plating layer that covers one surface side of the first plating layer and is formed as a single continuous piece without being divided into multiple pieces. A supply surface to 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. 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 passing the conductive material. The first plating layer comprises a reinforcing portion arranged to surround the periphery of the plurality of opening patterns, and a plurality of post portions. The plurality of post portions are arranged to surround each of the plurality of opening patterns.

[0007] A method for manufacturing a mask for mounting a conductive material according to the present disclosure is a method for manufacturing the above-mentioned mask for mounting a conductive material, and includes: a first step of forming a first resist on a base material so as to outline a region of the supply surface corresponding to a portion formed by a thin plate forming part; 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 region to leave a first plating layer on the base material after the second step; a fifth step of forming a second resist on a region 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 region of the base material after the fifth step to form a second plating layer.

[0008] The mask for applying a conductive material according to the present disclosure can improve durability.

[0009] 4 is a diagram showing an example of a plate provided with a mask for mounting a conductive material in embodiment 1. FIG. 5 is a diagram showing a cross section of the plate shown in FIG. 1. FIG. 6 is a diagram showing an example of a mask for mounting a conductive material. FIG. 7 is an enlarged view of part C in FIG. 3. FIG. 8 is a diagram showing a cross section taken along line D-D in FIG. 4. FIG. 9 is a diagram showing an example of a first plating layer. FIG. 10 is a flowchart showing an example of a method for manufacturing a mask for mounting a conductive material in embodiment 1. FIG. 11 is a diagram for explaining a method for manufacturing a mask for mounting a conductive material. FIG. 12 is a diagram for explaining a method for manufacturing a mask for mounting a conductive material. FIG. 13 is a diagram showing an example of a first resist formed on a base material in a first step. FIG. 14 is a diagram showing another example of a mask for mounting a conductive material. FIG. 15 is a diagram for explaining a step of forming a protrusion.

[0010] 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.

[0011] Embodiment 1. Fig. 1 is a diagram showing an example of a plate 1 provided with a mask 4 for mounting a conductive material in embodiment 1. 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 gauze 3, and a mask 4 for mounting a conductive material. The mask 4 for mounting a conductive material is attached to the frame 2 via the gauze 3. The gauze 3 is disposed around the mask 4 for mounting a conductive material. Tension is applied to the mask 4 for mounting a conductive material by the gauze 3.

[0012] 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, such as a substrate 5. When the conductive material is to be mounted onto the object, the conductive material mounting mask 4 is disposed above the object.

[0013] A large number of conductive materials are supplied to the supply surface 4a of the conductive material mounting mask 4. The supply surface 4a is flat. In the example shown in Figs. 1 and 2, the supply surface 4a faces upward. The conductive materials supplied to the supply surface 4a pass through the conductive material mounting mask 4 and are mounted at appropriate positions on the object to be mounted.

[0014] Fig. 3 is a diagram showing an example of a mask 4 for mounting a conductive material. Fig. 3 is a diagram showing the mask 4 for mounting a conductive material 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 an enlarged view of part C in Fig. 3. Fig. 5 is a diagram showing a cross section taken along the line D-D in Fig. 4. Fig. 2 shows a cross section corresponding to Fig. 5.

[0015] A plurality of opening patterns 6 are provided in the conductive material application mask 4. Fig. 3 shows an example in which the opening patterns 6 are regularly arranged in four vertical rows and four horizontal 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.

[0016] 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. 6 is a diagram showing an example of the first plating layer 10. Fig. 6 shows the conductive material mounting mask 4 shown in Fig. 3 from which the second plating layer 20 has been removed.

[0017] The first plating layer 10 can be formed simultaneously by a single plating process. The first plating layer 10 includes a reinforcing portion 11 and a plurality of post portions 12.

[0018] The reinforcing portion 11 is arranged so as to surround the periphery of the plurality of opening patterns 6. That is, the reinforcing portion 11 is arranged so as to surround the periphery of an opening pattern group made up of the plurality of opening patterns 6.

[0019] As an example, the reinforcing portion 11 has a square ring shape. The reinforcing portion 11 has a surface 11a and a surface 11b. The surfaces 11a and 11b are flat. The surface 11a faces upward when the mask 4 for mounting a conductive material is placed on an object to be mounted. The surface 11a is a surface that is visible when the mask 4 for mounting a conductive material is viewed from direction A shown in FIG. 2 . The surface 11a is a part of the supply surface 4a. The surface 11b faces in the opposite direction to the direction in which the surface 11a faces. The surface 11b faces downward when the mask 4 for mounting a conductive material is placed on an object to be mounted.

[0020] The plurality of post portions 12 are arranged so as to be separate and independent from each other. The plurality of post portions 12 are arranged so as to surround each of the plurality of opening patterns 6. That is, each of the plurality of opening patterns 6 is surrounded by a portion of the plurality of post portions 12 provided in the first plating layer 10.

[0021] As an example, each post portion 12 has a cylindrical shape. Each post portion 12 has a surface 12a and a surface 12b. The surfaces 12a and 12b are flat. The surface 12a faces upward when the conductive material loading mask 4 is placed on the object to be loaded. The surface 12a is the surface that is visible when the conductive material loading mask 4 is viewed from direction A shown in FIG. 2. The surface 12a is part of the supply surface 4a. The surface 12a is placed on the same plane as the surface 11a. The surface 12b faces in the opposite direction to the direction in which the surface 12a faces. The surface 12b faces downward when the conductive material loading mask 4 is placed on the object to be loaded. The surface 12b is placed on the same plane as the surface 11b.

[0022] Fig. 6 shows a preferred example in which the reinforcing portion 11 is formed as a single piece without being divided into multiple pieces. The reinforcing portion 11 may be divided into multiple pieces. For example, the reinforcing portion 11 may be divided into multiple individual pieces that have a rectangular ring shape as a whole. Figs. 3 and 6 show a preferred example in which the reinforcing portion 11 completely surrounds the entire periphery of the multiple opening patterns 6. It is preferred that the entire edge of the supply surface 4a is formed by the reinforcing portion 11.

[0023] FIG. 6 shows a preferred example in which the shape of each post portion 12 is different from the shape of the reinforcing portion 11. Also, FIGS. 3, 4, and 6 show a preferred example in which multiple post portions 12 are arranged to surround each opening pattern 6 in a double manner. That is, one opening pattern 6 is surrounded by a first post group in which a large number of post portions 12 are arranged in a regular pattern so that they form a square ring as a whole, and a second post group in which a large number of post portions 12 are arranged in a regular pattern so that they form a square ring as a whole. The opening pattern 6 is surrounded by the first post group, and the first post group is surrounded by the second post group. Between the first post group and the second post group, there is a square ring-shaped region where no post portions 12 are present. Also, FIG. 6 shows a preferred example in which each post portion 12 has the same shape. However, it is not necessary for all of the post portions 12 to have the same shape.

[0024] 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 one surface side. This one surface is the surface that faces downward when the conductive material mounting mask 4 is placed on the mounting object. That is, the second plating layer 20 covers the reinforcing portion 11 from the surface 11b side and covers each post portion 12 from the surface 12b side. In the example shown in this embodiment, the second plating layer 20 is formed as a single piece without being divided into multiple pieces. It is preferable that the second plating layer 20 cover the entire first plating layer 10 from this one surface side.

[0025] 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 of 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 a thick plate forming portion T1. The portion of the second plating layer 20 that does not overlap with the first plating layer 10 will also be referred to as a thin plate forming portion T2. ​​It is preferable that the thin plate forming portion T2 be composed only of the second plating layer 20.

[0026] The second plating layer 20 has a surface 20a. The surface 20a is the surface of the thin plate forming part T2, and is the surface that faces upward when the conductive material application mask 4 is placed on the object to be applied. The surface 20a is a part of the supply surface 4a. In other words, the surface 20a faces in the same direction as the surface 11a and the surface 12a. The surface 20a, the surface 11a, and the surface 12a form the same plane.

[0027] In the example shown in this embodiment, the area of ​​the supply surface 4a other than the surface 11a and the surface 12a is the surface 20a. That is, the supply surface 4a is formed by the first plating layer 10 and the thin plate forming portion T2 of the second plating layer 20. It is preferable that the area of ​​the supply surface 4a formed by the thin plate forming portion T2 is continuous without being divided into multiple parts. Note that this area may be divided into multiple parts. When this area is divided into multiple parts, it is preferable that at least one of the divided parts includes multiple opening patterns 6. It is even more preferable that each of the divided parts includes multiple opening patterns 6.

[0028] 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 T1 and a thin plate forming portion T2. ​​The surface 20a of the thin plate forming portion T2 is flush with the surfaces 11a and 12a. Therefore, the second plating layer 20 is not completely flat, and the opposing surface has irregularities.

[0029] The distance L1 between the supply surface 4a and the surface 20b of the thin plate forming unit T2 is smaller than the distance L2 between the supply surface 4a and the surface 20c of the thick plate forming unit T1. The surface 20b is the surface of the thin plate forming unit T2, 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 a part of the opposing surface. The surface 20c is the surface of the thick plate forming unit T1, 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 a part of the opposing surface. The surfaces 20b and 20c face in the same direction as the surfaces 11b and 12b.

[0030] 5, the opposing surface of the mask 4 for mounting a conductive material has a convex shape at the thick plate forming portion T1. In other words, the thin plate forming portion T2 has a concave shape. In this way, a concave portion is formed by the thin plate forming portion T2 on the opposing surface of the mask 4 for mounting a conductive material. Each opening pattern 6 is formed in the thin plate forming portion T2.

[0031] Next, a method for manufacturing the mask 4 for mounting a conductive material will be described with reference to Fig. 7 to Fig. 9. Fig. 7 is a flowchart showing an example of a method for manufacturing the mask 4 for mounting a conductive material in the first embodiment. Fig. 8 and Fig. 9 are diagrams for explaining the method for manufacturing the mask 4 for mounting a conductive material.

[0032] First, in S101, a first step is performed in which a first resist 31 is formed on a base material 30. In this embodiment, the resist is an example of a photosensitive material. In the first step, a conductive base material 30 is first prepared as shown in FIG. 8( a). Next, a layer of resist is formed on the surface 30 a of the base material 30, and then exposure and development are performed. As a result, the first resist 31 is formed on the surface 30 a of the base material 30 so as to outline a region corresponding to the portion of the supply surface 4 a formed by the thin plate forming portion T2. ​​Hereinafter, this region on the surface 30 a will be referred to as region F.

[0033] Fig. 10 is a diagram showing an example of the first resist 31 formed on the base material 30 in the first step. Fig. 10 is a diagram showing the surface 30a of the base material 30 as viewed from above, and shows a portion corresponding to E in Fig. 4. By performing the first step, the first resist 31 is formed on the surface 30a of the base material 30, as shown in Fig. 8(b).

[0034] 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 in an area of ​​the surface 30a where the first resist 31 is not present. In the following, the plating layer formed in the area F is denoted by the symbol J1. The plating layer formed in an area other than the area F is denoted by the symbol J2. By performing the second step, the base material 30 is plated, and as shown in FIG. 8(c), plating layers J1 and J2 are formed on the surface 30a.

[0035] After the second step, a third step is performed in S103 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.

[0036] 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. 8(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.

[0037] 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.

[0038] After the third and fourth steps, in S105, a fifth step is performed in which a second resist 32 is formed in a 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 are to be formed. In the fifth step, after the resist is formed in the 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. 9( a).

[0039] 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. 9( b). The plating layer formed in the sixth step is the second plating layer 20.

[0040] 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. 9( c ). The holes formed in the second plating layer 20 in the seventh step are through holes 7.

[0041] 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 the conductive material mounting mask 4 shown in Figures 3 to 5. Furthermore, by attaching the conductive material mounting mask 4 to the frame 2 via the gauze 3, the plate 1 shown in Figures 1 and 2 is completed.

[0042] In the mask 4 for mounting a conductive material, the first plating layer 10 includes a reinforcing portion 11 and a plurality of post portions 12. The reinforcing portion 11 is arranged so as to surround the periphery of an opening pattern group consisting of a plurality of opening patterns 6, and the plurality of post portions 12 are arranged so as to surround each opening pattern 6. Therefore, the periphery of the opening pattern group can be reinforced by the first plating layer 10, and the durability of the mask 4 for mounting a conductive material can be increased.

[0043] In order to provide a conductive material application mask 4 having excellent durability, it is preferable that the reinforcing portion 11 is formed as a single piece without being divided into multiple pieces. It is also preferable that the reinforcing portion 11 completely surrounds the periphery of the opening pattern group.

[0044] In the conductive material mounting mask 4, it is preferable that the region formed by the thin plate forming portion T2 on the 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, thereby minimizing the removal step and improving work efficiency.

[0045] 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.

[0046] 11 is a diagram showing another example of the conductive material mounting mask 4. FIG. 11 is a diagram showing the conductive material mounting mask 4 as viewed from the direction A in FIG. 2. The conductive material mounting mask 4 shown in FIG. 11 differs from the above-described example in that the region of the supply surface 4a formed by the thin plate forming portion T2 reaches the edge of the supply surface 4a in only one location. 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 edge of the plating layer formed on the base material 30, thereby improving work efficiency.

[0047] Fig. 12 is a diagram showing another example of the mask 4 for depositing a conductive material. Fig. 12 is a cross-sectional view corresponding to Fig. 5. The mask 4 for depositing a conductive material shown in Fig. 12 differs from the mask 4 for depositing a conductive material shown in Fig. 5 in that it further includes protrusions 13. The protrusions 13 protrude from the end face of the first plating layer 10 into the thin plate forming portion T2 of the second plating layer 20. Specifically, the protrusions 13 protrude from the end face of the reinforcing portion 11 into the thin plate forming portion T2. ​​The protrusions 13 protrude from the outer peripheral surface of the post portion 12 into the thin plate forming portion T2. ​​Fig. 12 shows an example in which the first plating layer 10 and the protrusions 13 are integrally formed.

[0048] 13A and 13B are diagrams illustrating the process of forming the protrusions 13. FIG. 13A corresponds to FIG. 8C, and FIG. 13B corresponds to FIG. 9C. When the protrusions 13 are to protrude from the end faces 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 13.

[0049] 13(b), the secondary plating is performed so that the protruding portions are completely hidden. In this example, the protrusions 13 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 13 is not limited to a hook shape.

[0050] The protrusions 13 may be provided only on the reinforcing portion 11 and not on each post portion 12 .

[0051] The present disclosure can be applied to a mask for mounting a conductive material.

[0052] DESCRIPTION OF SYMBOLS 1 Plate, 2 Frame, 3 Gauze, 4 Conductive material mounting mask, 4a Supply surface, 5 Substrate, 6 Opening pattern, 7 Through hole, 10 First plating layer, 11 Reinforcement portion, 11a to 11b Surface, 12 Post portion, 12a to 12b Surface, 13 Protrusion, 20 Second plating layer, 20a to 20c Surface, 30 Base material, 30a Surface, 31 First resist, 32 Second resist, T1 Thick plate forming portion, T2 Thin plate forming portion

Claims

1. A mask for mounting a conductive material comprising: a first plating layer; and a second plating layer covering one surface side of the first plating layer and formed as a single piece without being divided into multiple pieces, wherein a supply surface to 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, wherein a plurality of opening patterns are formed in the thin plate forming portion, and each of the plurality of opening patterns includes a plurality of through holes for passing a conductive material, and wherein the first plating layer comprises: a reinforcing portion arranged to surround the periphery of the plurality of opening patterns; and a plurality of post portions, wherein the plurality of post portions are arranged to surround each of the plurality of opening patterns.

2. The mask for mounting a conductive material according to claim 1, wherein said reinforcing portion is formed as a single continuous piece without being divided into a plurality of pieces.

3. The mask for mounting a conductive material according to claim 2, wherein the region of said supply surface formed by said thin plate forming portion reaches an edge of said supply surface at only one point.

4. The mask for mounting a conductive material according to claim 1 or 2, wherein the reinforcing portion completely surrounds the periphery of the plurality of opening patterns.

5. A mask for mounting a conductive material as claimed in any one of claims 1 to 4, wherein the plurality of post portions are arranged so as to surround each of the plurality of opening patterns doubly.

6. A mask for mounting a conductive material as claimed in any one of claims 1 to 5, wherein the area of ​​said supply surface formed by said thin plate forming portion is continuous without being divided into a plurality of parts.

7. A mask for mounting a conductive material as claimed in any one of claims 1 to 6, further comprising a protrusion protruding from an end face of said reinforcing portion into said thin plate forming portion.

8. A method for manufacturing a mask for mounting a conductive material according to any one of claims 1 to 7, comprising: a first step of forming a first resist on a base material so as to border an area corresponding to a portion of the 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 leaving the first plating layer on the base material by peeling off the plating formed in the area after the second step; a fifth step of forming a second resist in the 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 the second plating layer.

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