JP2022126740A - Mask for arrangement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mask for arrangement which can prevent mounting failure of a solder ball.

SOLUTION: A mask for arrangement mounts a solder ball 2 at predetermined position on workpiece 3 by pouring the solder ball 2 into a through hole 12 corresponding to a predetermined arrangement pattern, and includes a mask body 10 in which the through hole 12 is formed. At least a squeegee surface of the mask body 10 is provided with a coating layer made of a material with low friction.

SELECTED DRAWING: Figure 9

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to an alignment mask used, for example, to form solder bumps.

Solder bump formation methods include a printing process that applies flux to electrodes on workpieces such as wafers, flexible boards, and rigid boards, an arrangement process that arranges solder balls on the flux, and a heating process that heats and melts the solder balls. Bumps are formed through processes. In the arranging process described above, there is a transferring method using a mask as a method of arranging the solder balls on the workpiece. In the transfer method, an array mask (hereinafter simply referred to as a "mask") having through-holes for positioning through which the solder balls can be inserted corresponding to the array pattern of the electrodes of the work is used to transfer the solder balls to the work. It is mounted on the electrode of Specifically, after aligning the mask with the workpiece so that the through holes and the electrodes are aligned, the solder balls supplied on the mask are swept with a squeegee, a brush, or the like, and are aligned with the respective through holes. Insert solder balls one by one. By fixing the solder balls to the flux, the solder balls are temporarily mounted at predetermined positions on the workpiece.

As such a mask, there is one disclosed in Patent Document 1. The mask described in Patent Document 1 has a large number of supporting protrusions on the lower surface of a mask body having through holes, and the protrusion dimensions of the protrusions are set to be the same. As a result, when the mask is placed on the workpiece, the lower ends of all the supporting protrusions are brought into contact with the upper surface of the workpiece, ensuring a facing gap between the mask body having the through holes and the workpiece. ing.

JP 2006-287215 A

However, in recent years, along with the miniaturization of electronic devices, the miniaturization of bumps has progressed. In other words, as the bumps become smaller, the spacing between through holes and the spacing between pattern areas in the mask become narrower, and the external dimensions of the protrusions themselves arranged between the through holes and between the pattern areas (periphery of the pattern area) also become smaller. As a result, the gap between the mask and the workpiece is narrowed, and the flux placed on the electrode of the workpiece tends to adhere to the mask. In particular, if the flux adheres to the lower surface of the mask body or the inner surface of the through hole, mounting failure of the solder ball is likely to occur. SUMMARY OF THE INVENTION It is an object of the present invention to provide an arrangement mask capable of preventing mounting failures of solder balls.

The present invention is an array mask for mounting solder balls 2 at predetermined positions on a workpiece 3 by pouring the solder balls 2 into the through holes 12 corresponding to a predetermined array pattern. The mask body 10 has a mask body 10 in which a large number of regions are formed, and projections 15 provided on the side of the mask body 10 facing the workpiece 3, and a coating layer 50 is formed at least on the lower surface of the mask body 10. Characterized by Moreover, the mask main body 10 and the protrusion 15 are formed separately. Moreover, the coating layer 50 is formed so as to cover the lower surface of the mask body 10 and the surface of the protrusions 15 . This coating layer 50 is preferably formed with a thickness of 1 μm or less.

In addition, the present invention includes a mask body 10 in which a large number of pattern regions are formed with through holes 12, and projections 15 provided on the side of the mask body 10 facing the workpiece 3. At least the lower surface of the mask body 10 has 3 is a method of manufacturing an array mask on which a coating layer 50 is formed. First, a primary pattern resist 41 having a resist body 41a is formed on the master mold 40. As shown in FIG. Next, a primary electrodeposition layer 42 is formed on the master mold 40 using the resist body 41a. Next, a secondary pattern resist 44 having a resist body 44 a is formed on the primary electrodeposition layer 42 . Next, a coating layer 50 is formed on the surface of the primary electrodeposition layer 42 . The coating layer 50 is preferably formed on the surface of the primary electrodeposition layer 42 on which the secondary pattern resist 44 is provided and on the surface of the secondary pattern resist 44 .

According to the aligning mask of the present invention, since the coating layer is formed on the lower surface of the mask body, it is possible to prevent flux from remaining adhered to the lower surface of the mask body. In addition, by forming a coating layer so as to cover the lower surface of the mask body and the surface of the protrusions, the coating layer functions as a protective layer for the protrusions, preventing the protrusions from coming off, deforming, and breaking. can.

1 is a perspective view showing the overall configuration of an arraying mask and a work according to the present invention; FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is a longitudinal side view of the mask for arrangement|sequence which concerns on 1st Embodiment of this invention. 1 is a plan view of an array mask according to a first embodiment of the present invention; FIG. FIG. 4 is a longitudinal side view of another embodiment of the array mask according to the first embodiment of the present invention; FIG. 4 is a plan view of another embodiment of the array mask according to the first embodiment of the present invention; FIG. 4 is a longitudinal side view of another embodiment of the array mask according to the first embodiment of the present invention; FIG. 4 is an explanatory diagram of a method for manufacturing an array mask according to the first embodiment of the present invention; FIG. 4 is an explanatory diagram of a method for manufacturing an array mask according to the first embodiment of the present invention; FIG. 10 is a longitudinal side view of an arraying mask according to a second embodiment of the present invention; It is explanatory drawing of the manufacturing method of the mask for arrangement|sequence which concerns on 2nd Embodiment of this invention. It is explanatory drawing of the manufacturing method of the mask for arrangement|sequence which concerns on 2nd Embodiment of this invention. FIG. 5 is a partially enlarged plan view of an arraying mask according to another embodiment of the present invention; FIG. 11 is a partially enlarged longitudinal side view of another embodiment of the array mask according to the second embodiment of the present invention; It is explanatory drawing of the manufacturing method of another embodiment of the mask for arrangement|sequence based on 2nd Embodiment of this invention.

(First embodiment)
1 to 3 show a mask for arranging solder balls according to a first embodiment of the present invention. This arranging mask (hereinafter simply referred to as mask) 1 is used in the process of arranging solder balls 2 in forming solder bumps. In FIG. 2, reference numeral 3 denotes a workpiece on which solder balls 2 are to be mounted by the mask 1. As shown in FIG. The workpiece 3 is formed by, for example, mounting a plurality of semiconductor chips 5 on a base 4 of a glass epoxy substrate, wiring them by wire bonding, and then encapsulating them by transfer molding. Electrodes 6, which are input/output terminals, are formed in a predetermined pattern on the upper surface of 3. As shown in FIG. After forming the bumps, the work 3 is cut into individual pieces to form individual LSI chips.

As shown in FIG. 1, the mask 1 comprises a mask body 10 made of nickel, a nickel alloy such as nickel-cobalt, copper or other metal. 11 can be worn. In the central portion of the board surface of the mask main body 10, a large number of pattern regions each having a large number of independent through holes 12 for inserting the solder balls 2 are formed corresponding to the respective semiconductor chips 5. As shown in FIG. As shown in FIG. 2, the through holes 12 correspond to an array pattern corresponding to the array positions of the electrodes 6 of the semiconductor chips 5 on the workpiece 3 . The solder balls 2 have a radius of 50 μm or less, and accordingly, each through hole 12 is formed in a circular shape in a plan view having an inner diameter slightly larger than the radius of the balls 2. there is

The frame 11 is a flat plate made of a material such as aluminum, 42 alloy, invar, or SUS430. , one sheet of mask body 10 is held by one sheet of frame body 11. - 特許庁The frame 11 is a molded product thicker than the mask main body 10 and is inseparably and integrally joined to the outer peripheral edge of the mask main body 10 . Here, the thickness dimension of the frame 11 is, for example, about 0.05 to 1.0 mm, and is set to 0.5 mm in this embodiment. The thickness of the mask body 10 is preferably 10 μm or more, and is set to 200 μm in this embodiment.

On the lower surface side of the mask body 10 (mask 1 ), that is, on the surface facing the workpiece 3 , a projecting portion 15 projecting downward can be provided. Specifically, as shown in FIGS. 2 and 3, a projecting portion 15 (crosspiece 15a) can be provided between the pattern areas (on the periphery of the pattern area) so as to surround the pattern area. The projecting portion 15 (crosspiece 15a) may not be continuously provided as shown in FIG. 3, and may be provided fragmentarily. Further, as shown in FIG. 4, projections 15 (posts 15b) can be provided at positions in the pattern area where the through holes 12 are not formed. Further, the shape of the projections 15 provided between adjacent pattern areas (peripheries of the pattern areas) so as to surround the pattern areas is not limited to crosspieces 15a, but may be struts 15c as shown in FIG. If such a projecting portion 15 is provided, it can abut on the upper surface of the work 3 and secure a facing gap between the mask main body 10 and the work 3 during the arranging operation. As shown in FIGS. 2 and 4, each of the protrusions 15 (crosspieces 15a and struts 15b) is formed to taper from the lower surface of the mask body 10 toward the tip of the protrusion 15. As shown in FIGS. Preferably, it has a truncated cone shape.

As for the shape of the protrusion 15, as shown in FIG. 6, the root dimension of the protrusion 15 widens toward the lower surface of the mask body 10 (the shape narrows from the root to the tip of the protrusion 15). It may be tapered toward the end), and the side surface may be formed in an arc shape. As a result, it is possible to prevent damage caused by the concentration of stress on the base portion 15″ of the protrusion 15 in particular. Since the side surface of the projecting portion 15 is arc-shaped, the flux 17 can be prevented from entering the through hole 12 , so that the mounting failure of the solder ball 2 due to the flux 17 adhering to the through hole 12 can be prevented. The end position of the base portion 15'' of the protrusion 15 is preferably located near the through hole 12 on the lower surface of the mask body 10, and the lower surface 10a of the mask body and the inner surface 12a of the through hole , and a configuration in which it is located at a gap from the through hole 12 on the lower surface 10a of the mask body. Also, the side surface of the protrusion 15 may be either a convex arc or a concave arc. If the convex arc is used, the strength will be good, and if the concave arc is used, the flux 17 will flow at any position on the side surface of the protrusion 15. There is no part close to the electrode 6 to which the flux 17 is attached. Furthermore, the tip 15' and/or the root 15'' of the protrusion 15 may be formed in an arcuate shape, thereby minimizing the risk of the flux 17 adhering to the protrusion 15.

In the present mask 1, the ratio of the height of the protrusions 15 to the thickness of the mask body 10 is preferably 2:1 or more, and this is satisfied when the thickness of the mask body 10 is within the range of 10 to 300 μm. is more preferable. Moreover, the projection 15 preferably has a large aspect ratio (the ratio of the height of the projection 15 to the tip dimension), and the aspect ratio is 3 in this embodiment. Also, the base dimension L2 of the projection 15 is preferably 1.0 to 1.5 times the tip dimension L1 of the projection 15, and is set to 1.2 times in this embodiment. Furthermore, it is preferable that the ratio of the tip dimension L1, the root dimension L2 of the protrusion 15, and the width dimension L3 between the through holes 12 is 1:1.2:1.4 or more. Furthermore, the dimension L4 from the pattern area to the base of the protrusion 15 (crosspiece 15a, strut 15c) is preferably set to 0.01 mm or more, and is set to 0.02 mm in this embodiment. Such conditions can prevent the adhesion of flux as much as possible. At this time, by satisfying the relationship of the ratio between the tip dimension L1 and the root dimension L2 of the projection 15 and the relationship of the dimension L4 from the pattern area to the root of the projection 15, damage to the projection 15 can be prevented and the flux can be reduced. It is possible to achieve both prevention of adhesion of Furthermore, when the dimension from the pattern area to the center of the tip of the projecting portion 15 (crosspiece 15a, strut 15c) is L5, the ratio of L1 to L2 to L5 is 1:3:2.5 or more. It is possible to make the most of the above-mentioned coexistence effect.

Here, the mask 1 is formed by integrating the mask main body 10 and the protrusions 15, but the mask main body 10 and the protrusions 15 may be formed integrally with separate members. In the mask 1, if the mask main body 10 is made of a magnetic material and the protrusions 15 are made of a non-magnetic material, when the mask 1 is fixed to the workpiece 3 by the magnetic attraction of the magnet, Since the magnetic force can be uniformly exerted by the mask 1, there is no possibility that the mask 1 is unintentionally bent, the mask 1 can be brought into good contact with the work, and the alignment accuracy of the through hole 12 with respect to the electrode 6 can be improved. In addition, when the mask 1 is removed, the workpiece 3 and the protrusions 15 are not directly magnetically coupled, so that the stencil separation can be improved. Such a mask 1 can be obtained, for example, by forming the mask main body 10 from a magnetic metal (nickel, iron, etc.) and forming the protrusions 15 from a non-magnetic metal (copper, aluminum, etc.).

Moreover, in the case where the projecting portion 15 is formed of a non-magnetic material, it is not limited to the metal described above, and may be formed of resin or resist. As a result, in addition to the above effects, a cushioning effect derived from the elasticity of the resin is exhibited, and the work 3 is less likely to be damaged when the projecting portion 15 comes into contact with the work 3 . In addition, in order to exhibit such an effect remarkably, in the mask 1, it is preferable to form not only the protrusion 15 but also the entire portion of the mask 1 that comes into contact with the workpiece 3 with resin. Further, when forming the protrusions 15 from a resin, if the same resist as that used when forming the mask body 10 by electroforming is used, production efficiency can be improved.

Moreover, in the present mask 1, as shown in FIGS. 2, 4, and 6, a coating layer 50 is provided on the lower surface of the mask body 10 and the inner surface of the through hole 12. As shown in FIGS. As the coating layer 50, one having water repellency is preferable, and the material thereof includes fluorine resin, silicon resin, emulsion, resist (liquid), and the like. By providing the coating layer 50, even if the flux adheres to the lower surface of the mask main body 10 or the inner surface of the through hole 12, the flux can be repelled, and the state in which the flux adheres to the lower surface of the mask main body 10 or the inner surface of the through hole 12 can be prevented. can be prevented. The coating layer 50 may be formed on the upper surface of the mask body 10, or may not be formed on the lower surface of the mask body 10 between the pattern regions and between the protrusions 15 (crosspieces 15a and struts 15c). . In short, it is desirable to form the solder ball in a portion where mounting failure of the solder ball is likely to occur when the flux adheres. and preferably formed on the surface of the protrusion 15 .

In addition, each drawing does not show the appearance of the actual mask 1, but shows it schematically. Also, the opening dimension of the through hole 12, the thickness dimension of the mask body 10 and the like in each drawing are shown as such dimensions for the sake of convenience in preparing the drawings. 3 and 5, reference numeral 15 indicates the lower end surface (tip surface) of the protrusion 15, and the base of the protrusion 15 is not illustrated. 3 and 5, the coating layer 50 is not shown.

The procedure for arranging the solder balls 2 using the mask 1 is as follows. This arranging work is performed by a dedicated arranging device (see FIGS. 1, 5, etc. of Patent Document 1). First, the flux 17 (see FIG. 2) is applied by printing onto the electrodes 6 of the workpiece 3 . Next, after aligning the mask 1 on the workpiece 3 so that the through hole 12 and the electrode 6 are aligned, the mask 1 is fixed. Such alignment work is actually performed by aligning the outer peripheral edges of the frame 11 and the workpiece 3 . When the alignment work is completed, the lower end surface of the protrusion 15 contacts the surface of the work 3 in the fixed state, so that the mask body 10 is in contact with the work 3 as shown in FIGS. The posture is held in a separated posture in which a facing gap is ensured. At this time, it is also possible to place a magnet under the work 3 and attract the mask 1 to the work 3 side by the magnetic effect of this magnet.

Next, a large number of solder balls 2 are supplied onto the mask 1, the solder balls 2 are dispersed on the mask 1 using a squeegee brush, and the solder balls 2 are introduced into the through holes 12 one by one. As a result, the solder balls 2 are temporarily adhered and held on the electrodes 6 by the flux 17 . To prevent the mask 1 from being bent by the projecting part 15 even if a large squeegee brush pressure is applied to the mask 1 in the work of inputting the solder balls 2 using the squeegee brush, and to proceed smoothly with the work efficiency. can be done.

As described above, according to the mask 1 according to the present embodiment, since the protrusions 15 that form the gap between the mask body 10 and the work 3 are provided, the protrusions 15 ensure the gap between the work 3 and the mask. This ensures that the solder ball 2 can be efficiently inserted into the through hole 12 without omission.

A reinforcing frame 11 can be provided on the outer peripheral edge of the mask body 10, and if the mask body 10 is formed in a state in which tension is applied in a direction that causes the mask body 10 to contract inward, the surrounding area can be reduced. The expansion of the mask body 10 due to temperature change can be absorbed by the tension in the contraction direction. Thus, it is possible to prevent the mask body 10 from being displaced from the workpiece 3 . Further, since uniform tension can be applied to the entire mask body 10, the solder balls 2 can be mounted on the workpiece 3 with high positional accuracy.

Next, FIGS. 7 and 8 show a method of manufacturing the array mask 1 having such a configuration. First, for example, a photoresist layer 31 is formed on the surface of a conductive master mold 30 made of stainless steel or brass steel. The photoresist layer 31 is formed by laminating one or several sheets of a negative type photosensitive dry photoresist in accordance with a predetermined height and by thermocompression bonding. Next, as shown in FIG. 7(a), a pattern film (glass mask) 32 having transparent holes 32a corresponding to the projections 15 is adhered to the photoresist layer 31. Exposure is performed by irradiating light, development and drying are performed, and unexposed portions are removed by dissolving, as shown in FIG. A primary pattern resist 34 having a resist body 34 a was formed on the master mold 30 . At this time, it is preferable to taper the resist body 34a by using a photoresist that does not easily transmit ultraviolet rays, or by weakening the amount of exposure. Subsequently, the mold 30 is placed in an electroforming bath prepared under predetermined conditions, and as shown in FIG. A primary electroformed layer 35 was formed by electroforming an electrodeposited metal such as nickel or copper on the surface not covered with the coating. Here, the primary electroforming layer 35 was formed over substantially the entire surface of the matrix 30 (first electroforming step). Next, as shown in FIG. 7D, the primary pattern resist 34 is removed. Here, the surface of the primary electroformed layer 35 is preferably polished.

Next, as shown in FIG. 8(a), a photoresist layer 36 is formed on the entire surface of the primary electroformed layer 35 and the master mold 30, and the through hole 12 is formed on the surface of the photoresist layer 36. After a pattern film (glass mask) 37 having corresponding light-transmitting holes 37a is brought into close contact, exposure is performed by irradiating ultraviolet light from an ultraviolet light lamp 33, development and drying are performed, and unexposed portions are removed. By dissolving and removing, a secondary pattern resist 38 having a resist body 38a corresponding to the mask body 10 was formed on the surface of the primary electroformed layer 35, as shown in FIG. 8(b). Subsequently, it is placed in an electroforming bath prepared under predetermined conditions, and as shown in FIG. An electrodeposited metal such as nickel or copper was electroformed on the surface of the primary electroformed layer 35, which was free from the surface, to form a secondary electroformed layer 39 (second electroforming step). Next, the secondary pattern resist 38 is dissolved and removed, and the secondary electroformed layer 39 is separated from the master mold 30 and the primary electroformed layer 35 . Finally, a coating layer 50 is applied to the matrix surface side of the secondary electroformed layer 39 corresponding to the lower surface of the mask body 10 and the surface of the secondary electroformed layer 39 corresponding to the inner surface of the through hole 12 facing the secondary pattern resist 38 . By forming, the mask 1 as shown in FIG.8(e) and FIG.2 was obtained.

By attaching the frame 11 to the mask 1 thus obtained, the array mask 1 as shown in FIG. 1 is obtained. The mask 1 (secondary electroformed layer 39) can be held by the frame 11 in a state in which tension is applied to the mask 1 (secondary electroformed layer 39) so that stress in the direction of shrinking inward acts on itself. Such stress is applied by, for example, using the difference in coefficient of thermal expansion between the frame 11 and the mask 1, and the frame 11 is attached to the outer peripheral edge of the mask 1 in a high-temperature environment. can be realized by contracting inward.

According to the method of manufacturing the mask 1 as described above, the array mask can be manufactured with high accuracy using the electroforming method, so the solder balls 2 can be mounted on the workpiece 3 with high positional accuracy. In addition, if the mask body 10 and the protrusions 15 are integrally formed by electroforming the mask 1 having the protrusions 15 once (second electroforming process), the mask body 10 and the protrusions 15 is formed separately, there is less risk of problems such as breakage of the protrusions 15, and it is also excellent in that a highly reliable mask 1 can be obtained with high accuracy. Further, if the protrusion 15 is formed in a tapered shape so that it becomes larger as it approaches the lower surface of the mask main body 10, the concentration of stress particularly at the base of the protrusion 15 can be avoided, so that the strength of the protrusion 15 can be increased. While being firmly reinforced, the protrusions 15 can be in contact with the electrodes 6 while being separated from the electrodes 6 to which the flux 17 is applied. Poor mounting of the ball 2 can be prevented. At this time, it is more effective to set the ratio of the dimension of the tip portion 15′ and the dimension of the root portion 15″ of the protrusion 15 to 1:3 or more, and to set the aspect ratio of the protrusion 15 to 3 or more. Protrusions 15 having desired dimensions and aspect ratios can be easily produced by adjusting the shape of the resist pattern 35 .

In the mask 1 having such a configuration, the shapes of the through holes 12 and the protrusions 15 may be straight or tapered. Here, a case where the through hole 12 and the protrusion 15 are tapered will be described in detail. By providing the solder ball 2, it becomes easier to guide the solder ball 2 into the through hole 12, and by providing a taper that expands toward the surface of the mask main body 10 facing the work 3, the mask main body 10 faces the work 3. It is possible to prevent flux from adhering to the periphery of the through hole 12 on the surface side. In addition, by providing a tapered shape toward the surface of the mask body 10 facing the workpiece 3 in the protrusion 15, the mask can be firmly placed on the workpiece 3. By providing a taper that expands toward the surface of the mask body 10 facing the workpiece 3, the strength of the protrusions 15 is ensured even when the electrodes 6 of the workpiece 3 are arranged at a narrow pitch. At the same time, the contact of the projecting portion 15 with the workpiece 3 can be firmly handled. Such a shape can be easily obtained by changing the photosensitivity of the photoresist layers 31 and 36 and the exposure conditions.

(Second embodiment)
Next, an array mask according to the second embodiment will be described. In this embodiment, as shown in FIG. 9, the coating layer 50 is formed not only on the lower surface of the mask main body 10 but also on the surfaces of the protrusions 15 .

According to the array mask of the present embodiment, since the coating layer 50 is also formed on the surface of the projections 15, the adhesion of flux to the projections 15 can also be prevented. In addition, by forming the coating layer 50 on the lower surface of the mask body 10, the inner surface of the through hole 12, and the surface of the protrusion 15, even if flux adheres to the inner surface of the through hole 12, the flux is repelled and It can flow onto the workpiece through the surface of the protrusion 15 . In addition, it is possible to more reliably prevent the flux 17 from entering the through hole 12 .

Furthermore, by forming the coating layer 50 so as to cover the entire lower surface of the mask main body 10 and the entire surface of the projections 15, for example, when the mask main body 10 and the projections 15 are formed of separate members, the bonding strength between them is reduced. (This is because the spacing between through-holes and the spacing between pattern areas becomes narrower as the bumps become finer, and the external dimensions of the projections 15 arranged between the through-holes and between the pattern areas (periphery of the pattern area) also become smaller. (because the bonding area between the protrusion 15 and the mask body 10 is reduced), the protrusion 15 may fall off, deform, or break when the mask 1 is used. As a result, the coating layer 50 functions as a protective layer for the protrusions 15, which contributes to preventing the protrusions 15 from coming off, deforming, and breaking. If you want to specialize in preventing the projections 15 from coming off, deforming, and breaking, a metal layer (Ni, Cu, etc.) is formed on the lower surface of the mask body 10 and the surface of the projections 15 by sputtering or electroless plating. By doing so, the coating layer 50 may be provided.

10 and 11 show the method of manufacturing the array mask of this embodiment. First, as shown in FIG. 10(a), a matrix 40 is prepared. The matrix 40 may be of any type as long as it has electrical conductivity, and stainless steel is used in this embodiment. Next, a photoresist layer is formed on the surface of the matrix 40, exposed, developed, and dried by a known method, and the unexposed portions are removed by dissolution, resulting in the following as shown in FIG. 10(b). A primary pattern resist 41 having a resist body 41 a was formed on the master mold 40 . The photoresist layer was formed by laminating one or several negative type photosensitive dry film resists to a predetermined height. Next, the matrix 40 is placed in an electroforming bath prepared under predetermined conditions, and as shown in FIG. Electrodeposited metal was electroformed on the uncoated surface to form the primary electrodeposited layer 42 . In this embodiment, the primary electrodeposition layer 42 is formed by Ni—Co electroforming. After forming the primary electrodeposition layer 42, the surface of the primary electrodeposition layer 42 is preferably subjected to mechanical polishing such as belt polishing and/or electropolishing. Next, as shown in FIG. 10(d), the resist body 41a (resist pattern 41) was removed by dissolution.

Next, a solder resist layer 43 was formed on the surface of the primary electrodeposition layer 42 as shown in FIG. 11(a). The solder resist layer 43 is formed by laminating one or several layers in accordance with a predetermined height. Next, exposure, development, and drying are performed to dissolve and remove the unexposed portions, thereby forming a secondary pattern resist 44 having a resist body 44a on the primary electrodeposition layer 42, as shown in FIG. 11(b). integrally formed. After forming the secondary pattern resist 44, it is preferable to perform removal prevention treatment such as baking. Thereby, the adhesion between the secondary pattern resist 44 having the resist body 44a and the primary electrodeposition layer 42 can be made stronger. Next, as shown in FIG. 11(c), the primary electrodeposition layer 42 and the secondary pattern resist 44 formed on the surface thereof are removed from the master mold 40. Next, as shown in FIG. Finally, a coating layer 50 is formed on the surface of the primary electrodeposition layer 42 on which the secondary pattern resist 44 is provided and on the surface of the secondary pattern resist 44, thereby forming the array mask shown in FIGS. 11(d) and 9. 1 can be obtained. Note that the coating layer 50 may be formed before the primary electrodeposition layer 42 and the secondary pattern resist 44 are peeled off from the master mold 40 . Moreover, the coating layer 50 may be formed not only on the surface of the primary electrodeposition layer 42 having the secondary pattern resist 44 but also on the entire surface of the primary electrodeposition layer 42 . Of course, the coating layer 50 may be formed on the inner surface of the through hole 12 as well.

Next, another embodiment of the array mask according to the second embodiment will be described. Here, as shown in FIG. 13A, the protrusion 15 is made of resin, and a coating layer 70 is formed on the surface of the protrusion 15. The material of the coating layer 70 is It is made of a material different from the material of the protrusion 15 .

As described above, this mask is used to mount the solder balls on the electrodes of the workpiece. To remove this, wash the mask as needed. When cleaning the mask, a solvent is used, so the solvent may cause an adverse effect such as stickiness on the surface of the material that constitutes the protrusions. protect against such adverse effects.

Therefore, in the mask of the present embodiment, the coating layer 70 is formed on the surface of the protrusion 15 in order to prevent adverse effects on the protrusion 15 formed of resin. It is made of a material different from (resin). In addition to the above materials, the coating layer 70 can be formed of, for example, a photosensitive material containing an acrylic resin as a main component.

The method of manufacturing such an array mask is the same as the steps described above (see FIG. 10) from the preparation of the master mold to the formation of the primary electrodeposition layer and the removal of the resist body. Next, a solder resist layer is formed on the surface of the primary electrodeposition layer 42, and exposure, development, and drying are performed to obtain a secondary pattern resist having a resist body 60a as shown in FIG. 14(a). 60 was integrally formed on the primary electrodeposited layer 42 . Next, as shown in FIG. 14(b), a coating layer 70 is formed on the surface of the secondary pattern resist 60. Next, as shown in FIG. The coating layer 70 is an alkali-developable photosensitive material, and contains mainly acrylic resin (55-65%), barium sulfate (15-25%), and silicon dioxide (15-25%). Finally, the primary electrodeposition layer 42 is peeled off from the matrix 40 together with the secondary pattern resist 60 and the coating layer 70 formed on its surface, thereby forming the array mask 1 shown in FIGS. 14(c) and 13. Obtainable. The coating layer 70 may also be formed on the surface of the primary electrodeposition layer 42 on which the secondary pattern resist 60 is provided. Alternatively, the coating layer 70 may be formed after the secondary pattern resist 60 is formed on the primary electrodeposition layer 42 and then separated from the master mold 40 . By doing so, the coating layer 70 can be easily formed not only on the surface of the primary electrodeposition layer 42 having the secondary pattern resist 60 , but also on the entire surface of the primary electrodeposition layer 42 . The coating layer 70 may also be formed on the inner walls of the through holes 12 . In addition, after forming the secondary pattern resist 60 and the coating layer 70, it is preferable to perform removal prevention treatment such as baking. Thereby, the adhesion between the primary electrodeposition layer 42 and the secondary pattern resist 60 and between the secondary pattern resist 60 and the coating layer 70 can be made stronger. Such removal prevention treatment may be performed each time the secondary pattern resist 60 and the coating layer 70 are formed, or may be performed together after the coating layer 70 is formed on the surface of the secondary pattern resist 60 .

The mask 1 obtained by such a manufacturing method is resistant to cleaning (solvent), and can prevent the protrusions 15 from becoming sticky as much as possible. Further, as shown in FIG. 13(b), if the coating layer 70 is formed so as to cover the entire surface of the protrusion 15, the protrusion 15 can be prevented from being damaged or missing.

Here, since the projections 15 and the coating layer 70 are made of the same resin, the adhesion between the projections 15 and the coating layer 70 is strong. before forming the coating layer 70 on the surface of the protrusion 15), the protrusion 15 is washed to intentionally make the surface of the protrusion 15 sticky, and by forming the coating layer 70 on the surface, the protrusion 15 and the coating layer The adhesion force with 70 can be made stronger.

Moreover, as shown in FIG. 13(c), it is also possible to form the protruding portion 15 only from the material forming the coating layer 70. FIG. A material for forming the coating layer 70 is a material to which flux hardly adheres, and specifically, a resin mixture containing barium sulfate and/or silicon dioxide in an acrylic resin can be used. This resin mixture has excellent solvent resistance. Specifically, the resin mixture has a width of 0.2 to 3.0 mm (0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1.0 mm, 2.0 mm, 3.0 mm). A total of 7 products) are placed in a cleaning agent (manufactured by Kaken Tech Co., Ltd.) for 6 to 24 hours (a total of 6 hours, 12 hours, and 24 hours). 3 times), but it was confirmed that there was no peeling of the protrusions in all the masks. Furthermore, since such a resin mixture is compatible with the mask main body 10 and has good adhesion, it is possible to narrow the width dimension of the protrusion 15 . Since the resin mixture has hardness (5H to 6H in the JIS standard scratch hardness test), if the thickness of the mask body is 100 μm or less and the width dimension of the protrusion is larger than 5 mm, the mask will warp. Therefore, it is preferable that the width of the protrusion is 5 mm or less. As described above, the coating layer 70 is mainly composed of a material such as fluorine resin, silicon resin, acrylic resin, or the like. Then, it is possible to configure the protrusion 15 by using such a material as a main component.

The main component of the resin mixture forming the protrusions 15 is an acrylic resin, but is not limited thereto, and may be polyethylene, polypropylene, polystyrene, polyurethane, polyvinyl chloride, polyvinyl acetate, ABS resin, AS resin, PET resin, EVA resin, fluororesin, polyamide, polyacetal, polycarbonate, polyphenylene ether, polyester, polyolefin, polyphenylene sulfide, polytetrafluoroethylene, polysulfone, polyethersulfone, amorphous polyarylate, liquid crystal polymer, polyetheretherketone, polyimide, Examples include polyamideimide (so-called thermoplastic resin). Phenol resin, epoxy resin, melamine resin, urea resin, alkyd resin, polyurethane, etc. (so-called thermosetting resin) may also be used.

In each of the above embodiments, the protrusion 15 (support 15b) and the through hole 12 may be arranged so that the protrusion 15 (support 15b) surrounds one through hole 12, or one protrusion 15 may be arranged so as to be surrounded by the through hole 12 . When the protrusions 15 are arranged so as to surround one through hole 12, the shape of the protrusions 15 is not limited to being partially provided like a support, and may be provided in the shape of an endless frame. Moreover, the shape of the protrusion 15 is not limited to the crosspiece 15a or the column, but may be polygonal such as rhombus or hexagon, or ellipse. Further, among these shapes, as shown in FIG. 12, elongated shapes and/or rounded corners are preferred. In this way, by aligning the longitudinal direction and the major diameter direction of these shapes in a certain direction, for example, when cleaning the back surface of the mask 1, the cleaning means (cloth, sponge, etc.) is caught on the protrusions 15. It is possible to eliminate as much as possible the risk of damage to the projections 15 and to clean them smoothly. Therefore, it is desirable to align the longitudinal direction and major diameter direction of all the projections 15 in one direction. It should be noted that the elongated shape is limited to the lower end surface (tip surface) of the projection 15, and the surface of the root portion 15b of the projection 15 does not necessarily need to be elongated in terms of strength and the like.

Further, in each of the above-described embodiments, the thickness of the coating layers 50 and 70 may differ between the inner surface of the through hole 12 and the surfaces of the mask body 10 and the protrusions 15 . Specifically, when the thickness of the coating layer 50 on the inner surface of the through hole 12 is T1, and the thickness of the coating layer 50 on the surface of the mask body 10 and the protrusion 15 is T2 (see FIG. 9), T1>T2. By doing so, it is possible to more reliably prevent flux from adhering to the inner surface of the through-hole 12, which causes improper mounting of the solder ball. Also, if the coating layer 50 is made of a slippery (low friction) material, a slippery region will appear at the boundary between the upper surface of the mask body 10 and the inner surface of the through hole 12 by the thickness of T1. The thicker the solder ball 2, the larger the region becomes. Therefore, when the solder ball 2 is scratched with the squeegee brush, the squeegee brush and the solder ball 2 can be moved smoothly, and an improvement in productivity and work efficiency can be expected. If T1<T2, when the protrusion 15 is separately formed on the lower surface of the mask body 10, it is possible to more reliably prevent the protrusion 15 from coming off, deforming, and breaking. There are various methods for forming the coating layer 50, such as an immersion method and a spray method. When forming the coating layer 50, it is preferable to cover portions other than desired formation locations with a protective sheet. In addition, when the coating layer 50 is desired to be thickened, the portion to be thickened is locally sprayed, or the direction in which the mask 1 is immersed is changed (for example, when it is desired to be thickened at the bottom surface of the mask body 10, the bottom surface of the mask body 10 is and the immersion surface are parallel to each other, and if it is desired to increase the thickness of the inner surface of the through hole 12, the lower surface of the mask body 10 and the immersion surface should be immersed in a vertical state.

1 Mask 2 Solder Ball 3 Work 6 Electrode 10 Mask Main Body 12 Through Hole 15 Protruding Part 15a Crosspiece 15b Support 15c Support 15' Tip 15'' Root 30, 40 Base Mold 31, 36, 43 Photoresist Layer (Solder Resist Layer)
34, 41 primary pattern resist 34a, 41a resist body 35, 42 primary electrodeposition layer 38, 44, 60 secondary pattern resist 38a, 44a resist body 39 secondary electrodeposition layer 50, 70 coating layer

Claims (7)

An array mask for mounting the solder balls (2) at predetermined positions on a workpiece (3) by pouring the solder balls (2) into the through holes (12) corresponding to a predetermined array pattern,
A mask body (10) in which the through hole (12) is formed,
A mask for arraying, wherein a coating layer made of a material with low friction is provided on at least the squeegee surface of the mask body (10). 2. The arraying mask according to claim 1, wherein the coating layer made of a material with low friction is provided on the inner surface of the through hole (12). 3. The arraying mask according to claim 1, wherein the coating layer made of a material with low friction is provided on the surface of the mask body (10) facing the workpiece (3). . A projection (15) is provided on the surface of the mask body (10) facing the workpiece (3), and a coating layer formed of the material with low friction is formed on the surface of the projection (15). 4. The array mask according to any one of claims 1 to 3, further comprising: 2. The array mask according to claim 1, wherein a coating layer made of a water-repellent material is provided on the surface of the mask body (10) facing the workpiece (3). 6. The arraying mask according to claim 5, wherein the coating layer made of a material having water repellency is provided on the inner surface of the through hole (12). A projection (15) is provided on the surface of the mask body (10) facing the work (3), and the surface of the projection (15) is coated with the water-repellent material. 7. An alignment mask according to claim 5 or 6, characterized in that a layer is provided.

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