TWI869438B - Solder ball array mask - Google Patents

Abstract

The subject of the present invention is to solve the problem that the primary electrodeposition layer falls off from the secondary electrodeposition layer having the protrusion formed on the back of the mask, resulting in damage to the protrusion, thereby reducing the loading rate of the conductive solder ball. The solder ball array mask 1 of the present invention has an opening 30 corresponding to a specific array pattern, and the conductive solder ball is loaded at a specific position by loading the conductive solder ball into the above-mentioned opening 30. In addition, on the side of the solder ball array mask 1 opposite to the loaded body, there is a protrusion 2 formed by stacking the secondary electrodeposition layer 4 on the primary electrodeposition layer 3, and the primary electrodeposition layer 3 of the above protrusion 2 has a non-detachable structure that is not easy to fall off from the secondary electrodeposition layer 4. Furthermore, the primary electrodeposition layer 3 of the protrusion 2 is ring-shaped in a plan view, and a stopper 11 is provided at the interface between the primary electrodeposition layer 3 of the protrusion 2 and the secondary electrodeposition layer 4.

Description

Solder ball array mask

The present invention relates to a solder ball array mask suitable for arranging conductive solder balls and a manufacturing method thereof.

Conventionally, in a metal mask for a conductive solder ball array (hereinafter referred to as a mask), a mask having a recess formed on the periphery of an opening pattern on the substrate surface is used in order to prevent the flux formed on the electrode of the conductive solder ball mounting portion from adhering to the mask. As a method for forming the recess, a mask manufacturing method is disclosed as follows: a secondary electrodeposition layer is deposited on a primary electrodeposition layer by multiple electrocasting processes to form a convex portion, and a portion formed only by the secondary electrodeposition layer without the primary electrodeposition layer is used as a recess (see Patent Document 1).

In addition, as a method for manufacturing a mask in which a protrusion is formed by performing a plurality of electroplating processes, there is patent document 2 described below. The method for manufacturing a mask described in Patent Document 2 is a method for manufacturing a mask for a solder ball array, and is characterized in that the mask for a solder ball array comprises a mask body and protrusions, the mask body is formed by plating, and has a plurality of openings for inserting conductive solder balls to be loaded, the protrusions are formed by plating, and partially protrude beyond the openings on the back of the mask body, and the front end of the protrusions is formed into an R-shape with a rounded outer edge; and the method for manufacturing a mask for a solder ball array comprises the following steps: forming an anti-etching agent layer for forming the protrusions on a SUS base material; plating the SUS base material in such a manner that the protrusions have a specific height, thereby forming a first plating layer; After the formation of the first coating is completed, the anti-etching agent layer for forming the protrusion is removed; the first coating layer other than the protrusion is removed, and the protrusion formed by the first coating layer is left on the SUS base material; a plurality of anti-etching agent layers for forming openings are formed between the protrusions on the SUS base material; by making the mask body become a specified thickness The method of coating the SUS base material and the protrusions in a manner of degree to form a second coating layer; after the formation of the second coating layer is completed, the plurality of anti-etching agent layers for forming the openings are removed; and the coating layer of the protrusions and the mask body formed by the first coating layer and the second coating layer is peeled off from the SUS base material (refer to patent document 2). Furthermore, the electrocasting method and the electroplating method are only different in expression, and the technical contents are substantially the same. [Prior technical document] [Patent document]

[Patent document 1] Japanese Patent Publication No. 2010-247500 [Patent document 2] Japanese Patent Publication No. 2017-5053

[The problem the invention is trying to solve]

By the manufacturing method described in the above-mentioned patent document 1 or patent document 2, a protrusion (hereinafter also referred to as a protrusion or a convex portion) of any shape can be formed on the back of the mask. The protrusion is formed by stacking a secondary electrodeposition layer on the primary electrodeposition layer. The primary electrodeposition layer is formed by a primary electrocasting step, and the secondary electrodeposition layer is formed by a secondary electrocasting step. Therefore, there is a time difference between the two steps. In the primary electrocasting step and the secondary electrocasting step, even if the electrocasting conditions are set exactly the same, there will be a boundary between the primary electrodeposition layer and the secondary electrodeposition layer.

If there is a boundary, the adhesion at the interface between the primary electrodeposited layer and the secondary electrodeposited layer will be reduced. Even if the primary electrodeposited layer is subjected to chemical surface treatment such as hydrochloric acid treatment after the primary electrocasting step to improve the adhesion at the interface, there is a limit to the improvement of adhesion. In addition, if cleaning operations are repeatedly performed during the stage of repeated use of the mask, the following problem will occur: in the mask with low adhesion, the primary electrodeposited layer will fall off from the secondary electrodeposited layer with protrusions due to external force applied to the mask.

FIG10 shows a state in which a primary electrodeposition layer 3 is peeled off from a secondary electrodeposition layer 4 having a protrusion 2 formed thereon in a mask 1 manufactured by the prior art. FIG10(a) shows a normal state, and FIG10(b) shows a state in which an external force F is applied from the protrusion side (the back side of the mask). Since the thickness of the mask is as thin as tens of μm, if an external force is applied from the protrusion side, the mask is easily deformed. As a result, a gap is generated at the interface between the outer periphery of the primary electrodeposition layer and the secondary electrodeposition layer, and the primary electrodeposition layer is peeled off in a pushed-out manner. Although whether the primary electrodeposition layer falls off actually depends on the size of the external force, if the mask is used repeatedly, it is confirmed that a considerable amount of the primary electrodeposition layer with protrusions falls off.

If the primary electrodeposition layer falls off from the secondary electrodeposition layer on which the protrusions are formed, the strength of the protrusions as a whole may be reduced, resulting in the protrusions being damaged during use of the mask. As a result, there is a problem that the flux formed on the electrode of the conductive solder ball loading portion adheres to the mask, resulting in a reduction in the solder ball loading rate.

Furthermore, if the primary electrodeposition layer falls off from the secondary electrodeposition layer formed with the protrusions, a dent as a mark of the detachment is generated on the surface side of the mask on which the conductive solder balls are loaded, and therefore there is a problem that the conductive solder balls are hooked on the edge of the dent and cannot be accurately arranged. [Technical means for solving the problem]

The present invention is a solder ball array mask, which is characterized in that: it has an opening corresponding to a specific array pattern, and by loading the conductive solder ball into the opening, the conductive solder ball is placed at a specific position, and the solder ball array mask has a plurality of primary electrodeposition layers and a secondary electrodeposition layer: the plurality of primary electrodeposition layers are separated and formed at a plurality of locations on the surface side of the solder ball array mask, and the secondary electrodeposition layers are separated and formed at a plurality of locations on the surface side of the solder ball array mask. The secondary electrodeposition layer is integrally formed on a portion other than the primary electrodeposition layer and on the primary electrodeposition layer; the side of the solder ball array mask opposite to the carrier body has a protrusion formed by the primary electrodeposition layer and the secondary electrodeposition layer, and a stopper is provided at the interface between the primary electrodeposition layer and the secondary electrodeposition layer of the protrusion, so that the primary electrodeposition layer of the protrusion is not easy to fall off from the secondary electrodeposition layer. In addition, the solder ball array mask of the present invention is characterized in that the primary electrodeposition layer of the protrusion is annular in a plan view, and the stopper is the interface between the inner peripheral surface of the primary electrodeposition layer and the secondary electrodeposition layer. Furthermore, the solder ball array mask of the present invention is characterized in that the above-mentioned locking portion is mushroom-shaped or roughly hammer-shaped in cross-section. [Effect of the invention]

According to the mask of the present invention, the adhesion of the interface between the primary electrodeposition layer formed with the protrusion and the secondary electrodeposition layer can be improved, and the primary electrodeposition layer can be prevented from falling off from the secondary electrodeposition layer. As a result, the protrusion can be prevented from being damaged during the use of the mask, and the flux formed on the electrode of the conductive solder ball loading part will not adhere to the mask, thereby preventing the conductive solder ball loading rate from being reduced. In addition, since no dents are generated on the surface side of the mask where the conductive solder ball is loaded, the conductive solder ball can be arranged smoothly and reliably.

The following is a description of the method for implementing the present invention with reference to the drawings. In a solder ball array mask, a protrusion can be formed on the back of the mask by performing multiple electroplating steps. The protrusion of the prior art is formed by stacking a secondary electroplating layer on a primary electroplating layer, but the interface between the primary electroplating layer and the secondary electroplating layer has weak adhesion. If the mask is used repeatedly, the primary electroplating layer will fall off from the secondary electroplating layer.

Therefore, the inventors of the present invention have conducted careful research to improve the adhesion of the interface between the primary electrodeposition layer and the secondary electrodeposition layer. In order to improve the adhesion, it is possible to consider increasing the area of the interface itself. However, the size of the top view shape of the protrusion must have its limitations, and there is a limit to increasing the top view area of the primary electrodeposition layer constituting the protrusion. [Example 1]

FIG. 1 is an enlarged cross-sectional view schematically showing a protrusion 2 of a mask 1 of Example 1. The protrusion 2 shown in the figure is formed by stacking a secondary electrodeposition layer 4 on a primary electrodeposition layer 3, and the primary electrodeposition layer 3 is ring-shaped when viewed from above. The shape of the ring is not limited to a circle, and can also be an ellipse or an egg, or even a polygon, but in this embodiment it is a ring. In practice, since most masks have a size of several hundred mm on one side, thousands of protrusions 2 as shown in the figure will be formed on one mask.

If the top view shape of the primary electrodeposition layer 3 is set to a circular ring shape in this way, the area of the interface 5 between the primary electrodeposition layer 3 and the secondary electrodeposition layer 4 in the top view will be reduced on the inner side of the ring by an amount equivalent to the disappearance of the interface of the primary electrodeposition layer 3. On the other hand, since the secondary electrodeposition layer 4 is also formed on the inner side of the ring of the primary electrodeposition layer 3, a longitudinal ring-shaped interface 6 equivalent to the thickness of the primary electrodeposition layer 3 will be formed on the inner side of the ring, thereby increasing the area of the interface. For example, when the inner diameter of the ring is equal to the thickness of the primary electrodeposition layer 3, the area of the interface is relatively reduced by 0.75π (2.36) times. As a result, the overall area of the interface between the primary electrodeposition layer 3 and the secondary electrodeposition layer 4, including the interface 7 on the outer periphery of the ring-shaped primary electrodeposition layer 3, is increased.

Although the increase in interface area can effectively improve the adhesion of the interface between the primary electrodeposition layer 3 and the secondary electrodeposition layer 4, what is more important than increasing the area is that if the top view shape of the primary electrodeposition layer 3 is formed into a ring shape, then even if an external force F acts from the side of the protrusion 2, the ring-shaped primary electrodeposition layer 3 will be stuck on the secondary electrodeposition layer 4, thereby realizing a structure that is not easy to fall off.

In the mask 1 shown in FIG. 1 , since the thickness of the mask 1 is as thin as several tens of μm, if an external force F is applied from the side of the protrusion 2, the mask 1 is deformed, and a force to generate a gap is applied at the interface 7 between the outer peripheral surface of the primary electrodeposition layer 3 and the secondary electrodeposition layer 4. Moreover, a gap is actually generated at the interface 7 between the outer peripheral surface of the primary electrodeposition layer 3 and the secondary electrodeposition layer 4. On the other hand, since there is an interface 6 between the inner peripheral surface of the annular primary electrodeposition layer 3 and the secondary electrodeposition layer 4, if an external force F is applied from the side of the protrusion 2, the external force F acts on the interface 6 as a pushing force in a direction of expanding the diameter of the interface. Therefore, even if an external force F is applied, the primary electrodeposition layer 3 can be kept stuck at the interface 6 with the secondary electrodeposition layer 4 without damaging the adhesion at the interface 6, thereby preventing the primary electrodeposition layer 3 from falling off from the secondary electrodeposition layer 4 formed with the protrusion 2. [Example 2]

FIG2 is an enlarged cross-sectional view schematically showing the protrusion 2 of the mask 1 of Example 2. In the protrusion 2 of this example, the primary electrodeposition layer 3 is formed into an inverted mushroom shape when viewed in cross section. That is, it has a shape in which the mushroom-shaped umbrella 8 and the handle 9 are inverted. Therefore, even if an external force is applied from the side of the protrusion 2, a force of a magnitude that separates the primary electrodeposition layer 3 and the secondary electrodeposition layer 4 constituting the mushroom-shaped umbrella 8 will not be applied to the interface. Even if a relatively large force is applied, only a tiny gap will be formed at the interface 7 corresponding to the outer periphery of the mushroom-shaped handle 9, and part of the mushroom-shaped umbrella 8 will be stuck to the secondary electrodeposition layer 4. Therefore, even if an external force acts from the side of the protrusion 2, the primary electrodeposition layer 3 can be kept stuck in the stopper 11 of the secondary electrodeposition layer 4, thereby preventing the primary electrodeposition layer 3 from falling off from the secondary electrodeposition layer 4. [Example 3]

FIG3 is an enlarged cross-sectional view schematically showing the protrusion 2 of the mask 1 of Example 3. In the protrusion 2 of this example, the primary electrodeposition layer 3 is formed into a roughly spun hammer shape under cross-sectional view. Here, the so-called roughly spun hammer shape refers to a shape in which the diameter of the middle part of the cylinder is thick and the diameters of both ends gradually become thinner. The protrusion 2 in which the primary electrodeposition layer 3 is formed into a roughly spun hammer shape under cross-sectional view exerts the same effect as that of Example 2. That is, even if an external force is applied from the side of the protrusion 2, only a tiny gap is generated at the interface 7 of the portion corresponding to the outer periphery of the roughly spun-hammer-shaped primary electrodeposition layer 3, and the maximum diameter portion of the primary electrodeposition layer 3 is stuck at the stop portion 11 with the secondary electrodeposition layer. Therefore, even if an external force is applied from the side of the protrusion 2, the primary electrodeposition layer 3 can be kept stuck at the stop portion 11 with the secondary electrodeposition layer 4, thereby preventing the primary electrodeposition layer 3 from falling off from the secondary electrodeposition layer 4. [Explanation of the manufacturing method]

Based on the steps shown in FIG. 4 , the manufacturing method of the solder ball array mask of the first embodiment of the present invention is described in sequence.

As shown in FIG4(a), a master mold 20 is prepared, and a photoresist film 21 is formed on the surface of the master mold 20. The master mold 20 can be any material as long as it has conductivity, and in this embodiment, SUS (Stainless Steel) is used. Next, as shown in FIG4(b), a primary pattern resist film 22 is exposed on the photoresist film 21 using a well-known method.

As shown in FIG4(c), the primary pattern resist film 22 having the primary pattern drawn thereon is developed and dried, and the primary pattern resist film 22 is formed on the master mold 20. As shown in FIG5, the top view of the primary pattern resist film 22 formed in the steps up to this point is composed of a circular resist in the center and an annular resist formed concentrically therewith. Here, the primary pattern resist film 22 can be formed by laminating one or more sheets of a negative photosensitive dry film resist film at a specific height.

The master mold 20 formed with the primary pattern resist film 22 is placed in an electrocasting tank prepared under specific conditions, and as shown in FIG4(d), the electro-deposited metal is electro-casted on the surface of the master mold 20 not covered by the primary pattern resist film 22 until the height is the same as the primary pattern resist film 22, thereby forming a primary electro-deposited layer 3. Ni can be used as the electro-deposited metal to form the primary electro-deposited layer 3. Next, as shown in FIG4(e), the primary pattern resist film 22 is removed.

As shown in Fig. 4(f), the waste electro-deposition layer 23 which is not needed as a mask is removed. As shown in Fig. 6, the primary electro-deposition layer 3 formed in the steps up to this point has a ring shape in top view.

As shown in FIG4(g), a photoresist film 25 is formed on the surface of the primary electrodeposition layer 3 and the master mold 20. The photoresist film 25 is formed by laminating one or more sheets of a negative photosensitive dry film resist film at a specific height. Next, as shown in FIG4(h), a secondary pattern resist film 26 is exposed on the photoresist film 25 by a well-known method.

As shown in FIG. 4( i ), a secondary pattern resist film 26 is formed on the master mold 20 by developing the secondary pattern resist film 26 having the secondary pattern and removing the unexposed portion.

As shown in FIG4(j), Ni, which is the same material as the primary electrodeposition layer 3, is electrocast on the surface of the primary electrodeposition layer 3 formed on the master mold 20 and on the surface of the master mold 20 not covered by the secondary pattern anti-etching agent film 26 to form the secondary electrodeposition layer 4. In the steps up to this point, the top view shape of the protrusion 2 formed by the secondary electrodeposition layer 4 is an annular shape as shown in FIG7. However, in the case where the inner diameter of the annular primary electrodeposition layer 3 is small and the thickness of the secondary electrodeposition layer 4 is thick, the electrodeposition layer is also formed in the center of the protrusion 2, so that it is difficult to be recognized as an annular protrusion in appearance. Next, as shown in FIG. 4( k ), the secondary pattern resist film 26 is removed to form an opening 30 for arranging the conductive solder balls.

Then, as shown in FIG4(l), the integrated primary electrodeposition layer 3 and the secondary electrodeposition layer 4 are peeled off from the master mold 20, and the solder ball array mask 1 can be obtained. According to the solder ball array mask 1 manufactured by the above method, even if an external force F acts from the protrusion side, the primary electrodeposition layer 3 can be kept stuck to the secondary electrodeposition layer 4, thereby preventing the primary electrodeposition layer 3 from falling off from the secondary electrodeposition layer 4.

Next, the manufacturing method of the solder ball array mask 1 of the embodiment 2 of the present invention is described based on FIG8. The manufacturing method of the solder ball array mask 1 of the embodiment 2 is basically the same as the manufacturing method of the solder ball array mask 1 of the embodiment 1 shown in FIG4. Therefore, in FIG8, only the steps different from those in FIG4 are described.

The steps shown in Fig. 8(a)(b)(c) correspond to the steps shown in Fig. 4(d)(e)(f) of Example 1. Fig. 4(d)(e)(f) is a schematic enlarged cross-sectional view, but since it is necessary to further enlarge the cross-sectional view for explaining Example 2, Fig. 8(a)(b)(c) is a schematic enlarged cross-sectional view showing only the right half shown in Fig. 4(d)(e)(f).

In the step of forming the primary electro-deposition layer 3, as shown in FIG8(a), the master mold 20 formed with the primary pattern anti-etching agent film 22 is placed in an electro-casting tank prepared under specific conditions, and electro-deposition is performed in a manner that exceeds the thickness of the primary pattern anti-etching agent film 22. In this way, a so-called overhang is formed on the primary electro-deposition layer 3 and serves as a stopper 11. The amount of overhang can be controlled by the time of the electro-casting step. Next, as shown in FIG8(b), the primary pattern anti-etching agent film 22 is removed.

As shown in Fig. 8(c), the waste electrodeposition layer 23 which is not needed as a mask is removed. The cross-sectional shape of the primary electrodeposition layer 3 formed in the steps up to this point is an inverted mushroom shape.

Next, the manufacturing method of the solder ball array mask 1 of the embodiment 3 of the present invention is described based on the steps shown in FIG9. The manufacturing method of the solder ball array mask 1 of the embodiment 3 is basically the same as the manufacturing method of the solder ball array mask 1 of the embodiment 1 shown in FIG4. Therefore, in FIG9, only the steps different from those in FIG4 are described.

The steps shown in FIG. 9(a)(b)(c)(d)(e)(f) respectively correspond to the steps shown in FIG. 4(b)(c)(d)(e)(f)(j) of Example 1. Moreover, similarly to FIG. 8 showing Example 2, FIG. 9(a)(b)(c)(d)(e)(f) is a schematic enlarged cross-sectional view showing only the right half shown in FIG. 4(b)(c)(d)(e)(f)(j).

The manufacturing method of the solder ball array mask 1 of Example 3 is characterized by the step of exposing the primary pattern anti-etching agent film 22. The exposure can be performed using a commercially available laser beam exposure device, but the irradiation is performed with an intensity that is excess energy compared to the standard energy of the laser beam. In this way, since SUS material is used in the master mold and the surface is mirror-polished, the excess energy will be reflected on the surface of the master mold with halo. As a result, as shown in Figure 9(a), the side of the primary pattern anti-etching agent film 22 that is in contact with the master mold is solidified into a skirt shape.

Next, as shown in FIG9(b), the primary pattern anti-etching agent film 22 having the primary pattern is developed and dried to form the primary pattern anti-etching agent film 22 on the master mold 20. As shown in FIG9(c), the master mold 20 having the primary pattern anti-etching agent film 22 is placed in an electro-casting tank formed by a bath under specific conditions, and metal is electro-cast and deposited on the surface of the master mold 20 not covered by the primary pattern anti-etching agent film 22 until the height is the same as that of the primary pattern anti-etching agent film 22, thereby forming a primary electrodeposition layer 3.

Furthermore, as shown in FIG9(d), the primary pattern anti-etching agent film 22 is removed, and as shown in FIG9(e), the waste electrodeposition layer 23 that is not needed as a mask is removed. Then, after the same steps as FIG4(g)(h)(i), as shown in FIG9(f), Ni of the same material as the primary electrodeposition layer 3 is electroplated on the surface of the primary electrodeposition layer 3 and the master mold 20 to form a secondary electrodeposition layer 4. In this way, a primary electrodeposition layer 3 having a cross-sectional shape that is roughly a spinning hammer shape can be formed. [Results of the peeling test]

For Example 1, the following three types of mask samples were prepared, and the The dynamometer of the 3 mm piercing terminal was used to perform a detachment test by applying an external force of 100 N for 30 seconds from the protruding side of the mask. For the mask samples, the total thickness of the mask (the combined thickness of the primary electrodeposition layer and the secondary electrodeposition layer) was set to 45 μm, 80 μm, and 120 μm, respectively, the height of the protrusion was set to 25 μm, 50 μm, and 60 μm, respectively, and the diameter of the protrusion when viewed from above was about 200 μm. The test results showed that none of the protrusions fell off.

For Example 2 and Example 3, the following three types of mask samples were prepared in the same manner as Example 1, and the following three types of mask samples were prepared using The dynamometer of the 3 mm piercing terminal was used to perform a detachment test by applying an external force of 100 N for 30 seconds from the protruding side of the mask. For the mask samples, the total thickness of the mask (total thickness of the primary electrodeposition layer and the secondary electrodeposition layer) was set to 45 μm, 80 μm, and 120 μm, respectively, the height of the protrusion was set to 25 μm, 50 μm, and 60 μm, respectively, and the diameter of the protrusion when viewed from above was about 200 μm. The test results showed that none of the protrusions fell off.

For comparison, the protrusions of the prior art mask were also subjected to the same peeling test as in the above embodiment, and the results showed that most of the three types of protrusions fell off. Based on these test results, it can be confirmed that the interface adhesion between the primary electrodeposition layer and the secondary electrodeposition layer of the mask of the present invention is improved.

The present invention has been described above based on the embodiments, but the present invention is not limited to the above embodiments. For example, in the above embodiment 1, the top view shape of the primary electro-deposition layer forming the protrusion is set to a single circular ring, but the shape of the ring is not limited to the single ring shape, and can also be a multi-ring shape. In addition, in the above embodiment, the manufacturing method of the mask with the waste electro-deposition layer is described, but of course it can also be applied to the manufacturing method of the mask without the waste electro-deposition layer. [Industrial Applicability]

The solder ball array mask of the present invention can be applied to arranging conductive solder balls on a substrate, etc. The manufacturing method of the present invention can be used to manufacture a solder ball array mask that can prevent a primary electrodeposition layer from falling off from a secondary electrodeposition layer that forms a protrusion of the mask.

1: Mask for solder ball array (mask) 2: Protrusion (protrusion) 3: Primary electro-deposition layer 4: Secondary electro-deposition layer 5,6,7: Interface 8: Umbrella 9: Handle 11: Stopper 20: Mother mold 21: Photoresist film 22: Primary pattern anti-etching agent film 23: Waste electro-deposition layer 25: Photoresist film 26: Secondary pattern anti-etching agent film 30: Opening F: External force

FIG. 1 is an enlarged cross-sectional view schematically showing the protrusion of the mask of Example 1. FIG. 2 is an enlarged cross-sectional view schematically showing the protrusion of the mask of Example 2. FIG. 3 is an enlarged cross-sectional view schematically showing the protrusion of the mask of Example 3. FIG. 4(a) to (l) are step-illustrating views showing the method for manufacturing the mask of Example 1. FIG. 5 is a top view observed in the direction of the arrow A-A of FIG. 4(c). FIG. 6 is a top view observed in the direction of the arrow B-B of FIG. 4(f). FIG. 7 is a top view observed in the direction of the arrow C-C of FIG. 4(j). FIG. 8(a) to (c) are step-illustrating views showing the method for manufacturing the mask of Example 2. FIG. 9(a) to (f) are step-illustrating views showing the method for manufacturing the mask of Example 3. 10(a) and (b) are enlarged cross-sectional views schematically showing protrusions of a mask in the prior art.

1: Mask for solder ball array (mask)

2: Protrusion (protrusion)

3: Primary Electrodeposition Layer

4: Secondary electrodeposition layer

5: Interface

6: Interface

7: Interface

F: External force

Claims (3)

A solder ball array mask is characterized in that: it has an opening corresponding to a specific array pattern, and by loading a conductive solder ball into the opening, the conductive solder ball is placed at a specific position, and the solder ball array mask has a plurality of primary electrodeposition layers and a secondary electrodeposition layer, and the plurality of primary electrodeposition layers are separated and formed on the surface of the solder ball array mask. The secondary electrodeposition layer is integrally formed on a portion other than the primary electrodeposition layer and on the primary electrodeposition layer. On the side of the solder ball array mask opposite to the mounted body, there is a protrusion formed by the primary electrodeposition layer and the secondary electrodeposition layer, and a stopper is provided at the interface between the primary electrodeposition layer and the secondary electrodeposition layer of the protrusion. As in claim 1, the mask for solder ball array, wherein the primary electro-deposition layer of the protrusion is annular in plan view, and the stopper is the interface between the inner peripheral surface of the first electro-deposition layer and the secondary electro-deposition layer. As in claim 1, the solder ball array mask, wherein the above-mentioned stopper is mushroom-shaped or roughly hammer-shaped in cross-section.