JP2021114623A - Mask for arrangement - Google Patents

Abstract

To provide a mask for an arrangement, capable of preventing a mounting failure of a solder ball.SOLUTION: A mask for an arrangement, mounting a solder ball 2 at a predetermined position on a workpiece 3 by depositing the solder ball 2 into a penetration hole 12 corresponding to a predetermined arrangement pattern, comprises: a mask main body 10 in which a plurality of penetration holes 12 is formed; and a projection part 15 provided to an opposite surface side with the workpiece 3 of the mask main body 10. On a squeegee surface side of at least the mask main body 10, a coating layer formed by a material having a water repellency is provided.SELECTED DRAWING: Figure 1

Description

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

Solder bumps are formed by a printing process in which flux is applied to electrodes on workpieces such as wafers, flexible substrates, and rigid substrates, an arrangement process in which solder balls are arranged on the flux, and heating in which the solder balls are heated and melted. Bumps are formed through the process. Then, in the above-mentioned arrangement step, as a method of arranging the solder balls on the work, there is a transfer method using a mask. In the transfer method, the solder balls are worked by using an arrangement mask (hereinafter, appropriately simply referred to as "mask") having a positioning through hole through which the solder balls can be inserted corresponding to the arrangement pattern of the electrodes of the work. It is mounted on the electrode of. Specifically, after aligning the mask with respect to the work so that the through holes and the electrodes match, the solder balls supplied on the mask are swept with a squeegee, a brush, etc., and one for each through hole. Insert the solder balls one by one. Then, by fixing the solder balls to the flux, the solder balls are temporarily mounted at a predetermined position on the work.

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

Japanese Unexamined Patent Publication No. 2006-287215

However, in recent years, with the miniaturization of electronic devices, the size of bumps has been increasing. That is, as the bumps become smaller, the through-hole spacing dimension and the pattern area spacing dimension in the mask become narrower, and the outer dimensions of the protrusions themselves arranged between the through-holes and the pattern area (outer circumference of the pattern area) also become smaller. Since there is a tendency, the facing distance between the mask and the work is narrowed, and the flux arranged on the electrodes of the work tends to adhere to the mask. In particular, if flux adheres to the lower surface of the mask body or the inner surface of the through hole, the solder balls are likely to be improperly mounted. An object of the present invention is to provide an arrangement mask capable of preventing mounting defects of solder balls.

The present invention is an arrangement mask in which the solder balls 2 are mounted at predetermined positions on the work 3 by transferring the solder balls 2 into the through holes 12 corresponding to the predetermined arrangement pattern, and the pattern is composed of the through holes 12. A mask body 10 having a large number of regions formed thereof and a protrusion 15 provided on the side facing the work 3 of the mask body 10 are provided, and a coating layer 50 is formed at least on the lower surface of the mask body 10. It is a feature. Further, the mask body 10 and the protrusion 15 are formed separately. Further, the coating layer 50 is formed so as to cover the lower surface of the mask body 10 and the surface of the protrusion 15. The coating layer 50 may be formed with a thickness of 1 μm or less.

Further, the present invention includes a mask main body 10 in which a large number of pattern regions composed of through holes 12 are formed, and a protrusion 15 provided on the side facing the work 3 of the mask main body 10, and at least on the lower surface of the mask main body 10. , A method for 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 matrix 40. Next, the primary electrodeposition layer 42 is formed on the matrix 40 using the resist body 41a. Next, a secondary pattern resist 44 having a resist body 44a is formed on the primary electrodeposition layer 42. Next, the coating layer 50 is formed on the surface of the primary electrodeposition layer 42. The coating layer 50 may be formed on the surface of the primary electrodeposition layer 42 on the side having the secondary pattern resist 44 and on the surface of the secondary pattern resist 44.

According to the mask for arrangement of the present invention, since the coating layer is formed on the lower surface of the mask main body, it is possible to prevent the state where the flux remains attached to the lower surface of the mask main body. Further, by forming the coating layer so as to cover the lower surface of the mask body and the surface of the protrusion, the coating layer functions as a protective layer of the protrusion, and the protrusion can be prevented from falling off, deformed or damaged. can.

It is a perspective view which shows the whole structure of the mask for arrangement and work of this invention. It is a longitudinal side view of the array mask which concerns on 1st Embodiment of this invention. It is a top view of the array mask which concerns on 1st Embodiment of this invention. It is a longitudinal side view of another embodiment of the array mask which concerns on 1st Embodiment of this invention. It is a top view of another embodiment of the array mask which concerns on 1st Embodiment of this invention. It is a longitudinal side view of another embodiment of the array mask which concerns on 1st Embodiment of this invention. It is explanatory drawing of the manufacturing method of the array mask which concerns on 1st Embodiment of this invention. It is explanatory drawing of the manufacturing method of the array mask which concerns on 1st Embodiment of this invention. It is a longitudinal side view of the array mask which concerns on 2nd Embodiment of this invention. It is explanatory drawing of the manufacturing method of the array mask which concerns on 2nd Embodiment of this invention. It is explanatory drawing of the manufacturing method of the array mask which concerns on 2nd Embodiment of this invention. It is a partially enlarged plan view of the array mask which concerns on another embodiment of this invention. It is a partially enlarged longitudinal side view of another embodiment of the array mask which concerns on 2nd Embodiment of this invention. It is explanatory drawing of the manufacturing method of another embodiment of the array mask which concerns on 2nd Embodiment of this invention.

(First Embodiment)
1 to 3 show a mask for arranging solder balls according to the first embodiment of the present invention. This array mask (hereinafter, simply referred to as a mask) 1 is used in the process of arranging the solder balls 2 in the formation of solder bumps. In FIG. 2, reference numeral 3 indicates a work to which the solder ball 2 is mounted by the mask 1. The work 3 is formed by mounting a plurality of semiconductor chips 5 on a base 4 of a glass epoxy substrate, wiring them with a wire bond, and then transfer-molding them. The work 3 surrounds the semiconductor chips 5. Electrodes 6, which are input / output terminals, are formed on the upper surface of the third in a predetermined pattern. The work 3 is cut into individual pieces after the bumps are formed to form individual LSI chips.

As shown in FIG. 1, the mask 1 is composed of a mask body 10 formed of a nickel alloy such as nickel or nickel cobalt, copper or other metal as a material, and the mask body 10 has a frame body surrounding the mask body 10. 11 can be attached. A large number of pattern regions including a large number of independent through holes 12 for inserting the solder balls 2 are formed in the central portion of the board surface of the mask main body 10 corresponding to each semiconductor chip 5. As shown in FIG. 2, the through hole 12 corresponds to an arrangement pattern corresponding to the arrangement position of the electrodes 6 of each semiconductor chip 5 on the work 3. The solder ball 2 has a radial dimension of 50 μm or less, and each through hole 12 is formed in a circular shape in a plan view having an inner diameter dimension slightly larger than the radial dimension of the ball 2. There is.

The frame body 11 is a flat plate body made of a material such as aluminum, 42 alloy, Invar material, SUS430, etc., and has one square-shaped opening corresponding to the mask body 10 in the center of the board surface. , One mask body 10 is held by one frame body 11. The frame body 11 is a molded product thicker than the mask body 10, and is inseparably and integrally joined to the outer peripheral edge of the mask body 10. Here, the thickness dimension of the frame body 11 is set to, 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.

A downwardly projecting protrusion 15 can be provided on the lower surface side of the mask body 10 (mask 1), that is, on the side facing the work 3. Specifically, as shown in FIGS. 2 and 3, a protrusion 15 (crosspiece 15a) can be provided between the pattern regions (outer circumference of the pattern region) so as to surround the pattern region. The protrusion 15 (crosspiece 15a) does not have to be continuously provided as shown in FIG. 3, and may be provided in fragments. Further, as shown in FIG. 4, the protrusion 15 (support 15b) can be provided at a position in the pattern region where the through hole 12 is not formed. Further, the shape of the protrusion 15 provided so as to surround the pattern region between adjacent pattern regions (outer circumference of the pattern region) is not limited to the crosspiece 15a, and may be a support 15c as shown in FIG. If such a protrusion 15 is provided, it is possible to secure an opposing gap between the mask main body 10 and the work 3 in contact with the upper surface of the work 3 during the arranging work. As shown in FIGS. 2 and 4, each protrusion 15 (crosspiece 15a, support 15b) is formed so as to be narrowed from the lower surface of the mask body 10 toward the tip of the protrusion 15. Preferably, it has a truncated cone shape.

In addition to this, as shown in FIG. 6, the shape of the protrusion 15 is a divergent shape in which the root dimension of the protrusion 15 increases toward the lower surface of the mask body 10 (squeezing from the root to the tip of the protrusion 15). It may have a constricted shape) and the side surface may be formed in an arc shape. As a result, it is possible to prevent damage caused by stress concentration on the protrusion 15 particularly at the root portion 15, and even if the flux 17 adheres to the protrusion 15 when the mask 1 is placed on the work 3. Since the side surface of the protrusion 15 is an arc, it is possible to prevent the flux 17 from wrapping around into the through hole 12, so that the flux 17 may adhere to the through hole 12 and cause a mounting failure of the solder ball 2. It can be eliminated. The terminal position of the root 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. A form located at the intersection of the above, and a form located at a gap from the through hole 12 on the lower surface 10a of the mask body can be considered. Further, the side surface of the protrusion 15 may be either a convex arc or a concave arc, and if it is a convex arc, the strength will be good, and if it is a concave arc, the flux 17 will be generated at any position on the side surface of the protrusion 15. There may be no portion close to the attached electrode 6, that is, a state in which a constant distance from the attached electrode 6 may be maintained. Further, the tip portion 15'and / or the root portion 15 "of the protrusion portion 15 may be formed in an arc shape, whereby the possibility that the flux 17 adheres to the protrusion portion 15 is reduced as much as possible.

In the present mask 1, the ratio of the height of the protrusion 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. Further, the protrusion 15 preferably has a large aspect ratio (ratio of the height of the protrusion 15 to the tip dimension), and in the present embodiment, the aspect ratio is 3. Further, the root dimension L2 of the protrusion 15 is preferably 1.0 to 1.5 times the tip dimension L1 of the protrusion 15, and is set to 1.2 times in this embodiment. Further, it is preferable that the ratio of the tip dimension L1 of the protrusion 15 to the root dimension L2 and the width dimension L3 between the through holes 12 is 1: 1.2: 1.4 or more. Further, the dimension L4 from the pattern region to the root of the protrusion 15 (crosspiece 15a, support 15c) is preferably set to 0.01 mm or more, and is 0.02 mm in this embodiment. Under such conditions, the adhesion of flux can be prevented as much as possible. At this time, by satisfying the relationship between the ratio of the tip dimension L1 of the protrusion 15 and the root dimension L2 and the relationship of the dimension L4 from the pattern region to the root of the protrusion 15, the protrusion 15 is prevented from being damaged and the flux is satisfied. It is possible to achieve both prevention of adhesion. Furthermore, when the dimension from the pattern region to the center of the tip of the protrusion 15 (crosspiece 15a, support 15c) is L5, the ratio of L1, L2, and L5 is set to 1: 3: 2.5 or more. The above-mentioned compatibility effect can be maximized.

Here, the mask 1 in which the mask main body 10 and the protrusion 15 are integrated is used, but the mask main body 10 and the protrusion 15 may be integrally formed by separate members. This is because, in the mask 1, if the mask body 10 is made of a magnetic material and the protrusion 15 is made of a non-magnetic material, the mask 1 is fixed to the work 3 by magnetic force attraction of a magnet. Since the magnetic force can be applied uniformly, the mask 1 does not inadvertently bend, 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. Further, when the mask 1 is removed, the work 3 and the protrusion 15 are not directly magnetically coupled, so that the plate release can be improved. The mask 1 is obtained, for example, by forming the mask body 10 with a magnetic metal (nickel, iron, etc.) and the protrusion 15 with a non-magnetic metal (copper, aluminum, etc.).

Further, the protrusion 15 formed of a non-magnetic material is not limited to the above metal, and may be formed of a resin or a resist. As a result, in addition to the above effects, a cushioning action derived from the elasticity of the resin is exerted, and when the protrusion 15 comes into contact with the work 3, the possibility that the work 3 is damaged is reduced. In order to exert such an effect remarkably, it is preferable that not only the protrusion 15 but also the entire portion in contact with the work 3 is made of resin in the mask 1. Further, when the protrusion 15 is formed of resin, it can be formed with high production efficiency by using the same resist used when forming the mask body 10 by the electroforming method.

Further, 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 main body 10 and the inner surface of the through hole 12. The coating layer 50 preferably has water repellency, and examples of the material thereof include fluororesin, silicone resin, emulsion, and resist (liquid). By providing the coating layer 50, the flux can be repelled even if the flux adheres to the lower surface of the mask main body 10 and the inner surface of the through hole 12, and the state in which the flux remains attached to the lower surface of the mask main body 10 and the inner surface of the through hole 12 can be maintained. Can be prevented. The coating layer 50 may be formed on the upper surface of the mask main body 10, or may not be formed on the lower surface of the mask main body 10 between the pattern regions and between the protrusions 15 (crosspieces 15a and columns 15c). .. In short, it is desirable to form the mask in a portion where the solder balls are likely to be improperly mounted when the flux adheres, and when the mask 1 is placed on the work, the mask body 10 faces the flux 17 applied on the electrode 6. And it is desirable to form it on the surface of the protrusion 15.

It should be noted that each drawing does not show the actual state of the mask 1, but schematically shows it. Further, the opening size of the through hole 12 and the thickness size of the mask body 10 and the like in each drawing are shown in such dimensions for convenience of drawing. Further, in FIGS. 3 and 5, what is illustrated by reference numeral 15 is the lower end surface (tip surface) of the protrusion 15, and the root of the protrusion 15 is not shown. Further, in FIGS. 3 and 5, the coating layer 50 is not shown.

The work of arranging the solder balls 2 using the mask 1 is performed by the following procedure. 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 printed and applied on the electrode 6 of the work 3. Next, the mask 1 is aligned on the work 3 so that the through hole 12 and the electrode 6 are aligned, and then the mask 1 is fixed. Such alignment work is actually performed by aligning the outer peripheral edges of the frame 11 and the work 3. When the alignment work is completed, the lower end surface of the protrusion 15 comes into contact with 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. 2, 4, and 6. The posture is maintained in a separated posture in which the facing gap is secured. At this time, a magnet can be arranged below the work 3 and the mask 1 can be attracted to the work 3 by the magnetic action of the 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 thrown into the through holes 12 one by one. As a result, the solder balls 2 are temporarily fixed and held on the electrodes 6 by the flux 17. In the soldering ball 2 loading operation using such a squeegee brush, even if a large squeegee brush pressure is applied to the mask 1, the mask 1 can be prevented from bending due to the protrusions 15, and the loading operation can proceed smoothly and efficiently. Can be done.

As described above, according to the mask 1 according to the present embodiment, since the protrusion 15 that forms the facing gap between the mask body 10 and the work 3 is provided, the protrusion 15 ensures the facing gap with the work 3. It is possible to efficiently proceed with the work of inserting the solder ball 2 into the through hole 12 without omission.

A frame body 11 for reinforcement 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 stress in the direction of contracting inward acts on itself, the surroundings can be formed. The expansion of the mask body 10 due to the change in temperature can be absorbed by the tension in the contraction direction. This makes it possible to prevent the mask body 10 from being displaced with respect to the work 3. Further, since a uniform tension can be applied to the entire mask body 10, the solder balls 2 can be mounted on the work 3 with high positional accuracy.

Next, a method of manufacturing the array mask 1 having such a configuration is shown in FIGS. 7 and 8. First, for example, the photoresist layer 31 is formed on the surface of the base 30 made of conductive stainless steel or brass. The photoresist layer 31 was formed by laminating one or several negative type photosensitive dry photoresists according to a predetermined height and thermocompression bonding. Then, as shown in FIG. 7A, a pattern film (glass mask) 32 having a light-transmitting hole 32a corresponding to the protrusion 15 is brought into close contact with the photoresist layer 31, and then ultraviolet rays are emitted by an ultraviolet light lamp 33. As shown in FIG. 7B, the unexposed portion is dissolved and removed by irradiating with light to perform exposure, developing, and drying, thereby corresponding to the constricted protrusion 15. A primary pattern resist 34 having a resist body 34a 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 exposure amount. Subsequently, the mother mold 30 is placed in an electroformed tank that has been bathed under predetermined conditions, and as shown in FIG. 7 (c), the resist body 34a of the mother mold 30 is within the height range of the resist body 34a. A primary electroformed layer 35 was formed by electroforming an electrodeposited metal such as nickel or copper on a surface not covered with. Here, the primary electroforming layer 35 was formed over substantially the entire surface of the master mold 30 (first electroforming step). Next, as shown in FIG. 7D, the primary pattern resist 34 is removed. Here, it is preferable to polish the surface of the primary electroformed layer 35.

Next, as shown in FIG. 8A, a photoresist layer 36 is formed on the entire surface of the primary electroforming layer 35 and the master mold 30, and then the through hole 12 is formed on the surface of the photoresist layer 36. After the pattern film (glass mask) 37 having the corresponding translucent hole 37a is brought into close contact with the film, the unexposed portion is exposed by irradiating it with ultraviolet light with an ultraviolet light lamp 33, and then developing and drying the unexposed portion. By dissolving and removing, as shown in FIG. 8B, a secondary pattern resist 38 having a resist body 38a corresponding to the mask body 10 was formed on the surface of the primary electrolytic casting layer 35. Subsequently, it was placed in an electroformed tank that had been bathed under predetermined conditions, and as shown in FIG. 8 (c), it was covered with the master mold 30 and the resist body 38a within the height range of the previous resist body 38a. A secondary electroformed layer 39 was formed by electroforming a electrodeposited metal such as nickel or copper on the surface of the primary electroformed layer 35 (second electroforming step). Next, the secondary pattern resist 38 is melted and removed, and the secondary electroformed layer 39 is peeled off from the master mold 30 and the primary electroformed layer 35. Finally, the coating layer 50 is applied to the 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, a mask 1 as shown in FIGS. 8 (e) and 2 was obtained.

If the frame body 11 is attached to the mask 1 thus obtained, the array mask 1 as shown in FIG. 1 can be obtained. The mask 1 (secondary electroformed layer 39) can be held by the frame 11 in a state in which tension is applied to itself so that stress in the direction of contraction acts inward. To apply such stress, for example, the frame 11 is attached to the outer peripheral edge of the mask 1 in a high temperature environment by utilizing the difference in the coefficient of thermal expansion between the frame 11 and the mask 1, and the mask 1 is attached at room temperature. Can be achieved by contracting inward.

According to the method for manufacturing the mask 1 as described above, the mask for arrangement can be manufactured with high accuracy by using the electroforming method, so that the solder balls 2 can be mounted on the work 3 with high positional accuracy. Further, if the mask 1 having the protrusion 15 is formed by electroforming once (second electroforming step) so that the mask body 10 and the protrusion 15 are inseparably and integrally formed, the mask body 10 and the protrusion 15 are formed. Compared with the one formed by forming the 15 separately, there is less possibility that the protrusion 15 is damaged or other inconveniences occur, and the mask 1 having excellent reliability can be obtained with high accuracy. Further, if the protrusions 15 are formed in a constricted shape so as to become larger as they approach the lower surface of the mask body 10, stress is prevented from being concentrated especially at the roots of the protrusions 15, so that the strength of the protrusions 15 is increased. Since the protrusions 15 can be brought into contact with the electrodes 6 in a state of being separated from the electrodes 6 coated with the flux 17 while being firmly reinforced, the flux 17 coated on the electrodes 6 adheres to the mask body 10 to solder. It is possible to prevent the mounting failure of the ball 2. At this time, it is more effective to set the ratio of the dimension of the tip portion 15'of the protrusion 15 to the dimension of the root portion 15 "to 1: 3 or more and the aspect ratio of the protrusion 15 to 3 or more. The production of the protrusion 15 having such a desired size and aspect ratio can be easily obtained by adjusting the shape of the resist pattern 35.

In the mask 1 having such a configuration, the shape of the through hole 12 and the protrusion 15 may be straight or tapered. Here, a case where the through hole 12 and the protrusion 15 are tapered will be specifically described. In the through hole 12, the taper of the mask body 10 toward the work 3 facing the work 3 is tapered. By providing the solder ball 2, it becomes easy to lure the solder ball 2 into the through hole 12, and by providing a taper in a protruding shape toward the facing surface side of the mask main body 10 with 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. Further, in the protrusion 15, the mask can be firmly placed on the work 3 by providing a taper in the shape of a constriction toward the side of the mask body 10 facing the work 3. By providing a taper that extends toward the surface of the mask body 10 facing the work 3, the strength of the protrusions 15 is ensured even when the electrodes 6 of the work 3 are arranged at a narrow pitch. At the same time, the contact of the protrusion 15 on the work 3 can be firmly dealt with. Such a shape can be easily obtained by changing the photosensitivity and exposure conditions of the photoresist layers 31 and 36.

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

According to the array mask of the present embodiment, since the coating layer 50 is also formed on the surface of the protrusion 15, it is possible to prevent the flux from adhering to the protrusion 15. Further, by forming the coating layer 50 on the lower surface of the mask main body 10, the inner surface of the through hole 12, and the surface of the protrusion 15, even if the flux adheres to the inner surface of the through hole 12, the flux is repelled, and the lower surface of the mask main body 10 and the surface of the protrusion 15 are formed. It can flow on the work through the surface of the protrusion 15. In addition, it is possible to more reliably prevent the flux 17 from wrapping around into the through hole 12.

Further, by forming the coating layer 50 so as to cover the entire lower surface of the mask body 10 and the surface of the protrusion 15, for example, when the mask body 10 and the protrusion 15 are formed of different members, the bonding strength between the two is increased. Weak (this is because the hole spacing dimension and the pattern area spacing dimension become narrower as the bumps become finer, and the external dimensions of the protrusions 15 themselves arranged between the through holes and the pattern region (outer circumference of the pattern region) are also smaller. This is due to the fact that the joint area between the protrusion 15 and the mask body 10 becomes smaller), and the protrusion 15 may inadvertently 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, so that it can also contribute to preventing the protrusions 15 from falling off, deforming, or being damaged. If you want to specialize in preventing the protrusions 15 from falling off, deforming, or breaking, a metal layer (Ni, Cu, etc.) is formed on the lower surface of the mask body 10 and the surface of the protrusions 15 by sputtering or electroless plating. By doing so, it is preferable to provide the coating layer 50.

10 and 11 show a method for manufacturing an array mask according to this embodiment. First, as shown in FIG. 10A, a mother die 40 is prepared. The mother die 40 may be any as long as it has conductivity, and stainless steel is used in this embodiment. Next, a photoresist layer was formed on the surface of the mother die 40, and each treatment of exposure, development, and drying was performed by a well-known method to dissolve and remove the unexposed portion, as shown in FIG. 10 (b). A primary pattern resist 41 having a resist body 41a was formed on the matrix 40. The photoresist layer was formed by laminating one or several negative type photosensitive dry film resists at a predetermined height. Next, the mother mold 40 is placed in an electroformed tank that has been bathed under predetermined conditions, and as shown in FIG. 10 (c), it is covered with the resist body 41a of the mother mold 40 to the same height as the resist body 41a. Electroformed metal was electroformed on the unbroken surface to form the primary electrodeposition layer 42. In this embodiment, the primary electrodeposition layer 42 is formed by Ni—Co electroforming. After forming the primary electrodeposition layer 42, it is preferable to perform mechanical polishing such as belt polishing and / or electrolytic polishing on the surface of the primary electrodeposition layer 42. Then, as shown in FIG. 10 (d), the resist body 41a (resist pattern 41) was dissolved and removed.

Next, as shown in FIG. 11A, a solder resist layer 43 was formed on the surface of the primary electrodeposition layer 42. The solder resist layer 43 was formed by laminating one or several sheets according to a predetermined height. Next, by performing exposure, development, and drying treatments to dissolve and remove the unexposed portion, as shown in FIG. 11B, the secondary pattern resist 44 having the resist body 44a is placed on the primary electrodeposition layer 42. Formed integrally with. After forming the secondary pattern resist 44, it is preferable to perform a dropout prevention treatment such as baking. As a result, the adhesion between the secondary pattern resist 44 having the resist body 44a and the primary electrodeposition layer 42 can be further strengthened. Next, as shown in FIG. 11 (c), the primary electrodeposition layer 42 and the secondary pattern resist 44 formed on the surface thereof are peeled off from the master die 40. Finally, the array mask shown in FIGS. 11 (d) and 9 is formed by forming the coating layer 50 on the surface of the primary electrodeposition layer 42 on the side having the secondary pattern resist 44 and on the surface of the secondary pattern resist 44. 1 can be obtained. 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. Further, the coating layer 50 is not limited to the surface of the primary electrodeposition layer 42 on the side having the secondary pattern resist 44, and may be formed on the entire surface of the primary electrodeposition layer 42. Of course, the coating layer 50 may also be formed on the inner surface of the through hole 12.

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 the coating layer 70 is formed on the surface of the protrusion 15, and the coating layer 70 is used as a material. 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 work, but dirt etc. may adhere to the mask during the process of arranging the solder balls (mounting by transfer). To remove this, clean the mask as needed. Since the mask is cleaned using a solvent, this solvent may cause adverse effects such as stickiness on the surface of the material constituting the protrusions, but due to the coating layer on the surface of the protrusions, It protects against such adverse effects.

Therefore, in the mask of the present embodiment, a coating layer 70 is formed on the surface of the protrusion 15 in order to prevent an adverse effect on the protrusion 15 formed of the resin, and the coating layer 70 is a material forming the protrusion 15. 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 for producing the array mask is the same as the above-described step (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 each treatment of exposure, development, and drying is performed. As shown in FIG. 14A, a secondary pattern resist having a resist body 60a is formed. 60 was integrally formed on the primary electrodeposition layer 42. Next, as shown in FIG. 14B, a coating layer 70 is formed on the surface of the secondary pattern resist 60. The coating layer 70 is an alkali-developed photosensitive material, and the main components are acrylic resin (55 to 65%), barium sulfate (15 to 25%), and silicon dioxide (15 to 25%). Finally, by peeling the primary electrodeposition layer 42 from the matrix 40 together with the secondary pattern resist 60 and the coating layer 70 formed on the surface thereof, the array mask 1 shown in FIGS. 14 (c) and 13 is obtained. Obtainable. The coating layer 70 may also be formed on the surface of the primary electrodeposition layer 42 on the side having the secondary pattern resist 60. Further, the coating layer 70 may be formed after the secondary pattern resist 60 is formed on the primary electrodeposition layer 42 and then peeled off from the master die 40. By doing so, the coating layer 70 can be easily formed not only on the surface of the primary electrodeposition layer 42 on the side 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 wall of the through hole 12. Further, after forming the secondary pattern resist 60 and the coating layer 70, it is preferable to perform a dropout prevention treatment such as baking. As a result, the adhesion between the primary electrodeposition layer 42 and the secondary pattern resist 60, and the secondary pattern resist 60 and the coating layer 70 can be further strengthened. The dropout prevention treatment may be performed every 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 the manufacturing method is resistant to cleaning (solvent), and the protrusion 15 can be prevented from becoming sticky as much as possible. Further, as shown in FIG. 13B, 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 protrusion 15 and the coating layer 70 are made of the same resin, the adhesion between the protrusion 15 and the coating layer 70 is strong, but after the protrusion 15 is formed on the mask body 10 (the protrusion 15). Before forming the coating layer 70 on the surface of the protrusion 15), the protrusion 15 is washed to cause stickiness on the surface of the protrusion 15, and the coating layer 70 is formed on the surface of the protrusion 15 to form the protrusion 15 and the coating layer. The adhesion with the 70 can be made stronger.

Further, as shown in FIG. 13C, the protrusion 15 can be formed only by the material forming the coating layer 70. The material forming the coating layer 70 is one in which flux does not easily adhere, and specific examples thereof include a resin mixture containing barium sulfate and / or silicon dioxide in an acrylic resin. This resin mixture has excellent solvent resistance. Specifically, the width dimension of the resin mixture is 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). Each mask with protrusions on the mask body made of nickel-cobalt alloy was applied to a detergent (manufactured by Kaken Tech Co., Ltd.) for 6 to 24 hours (6 hours, 12 hours, 24 hours). Although it was immersed 3 times), it was confirmed that the protrusions were not peeled off in all the masks. Further, since the resin mixture has good compatibility with the mask body 10 and good adhesion, the width dimension of the protrusion 15 can be narrowed. Since the resin mixture has hardness (5H to 6H in the scratch hardness test of JIS standard), 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 warps. It is preferable that the width dimension of the protrusion is 5 mm or less because there is a risk of the protrusion. As described above, the coating layer 70 is formed mainly of a material such as a fluororesin, a silicone resin, or an acrylic resin. Then, it is possible to form the protrusion 15 with the material as the main component.

The main component of the resin mixture forming the protrusion 15 is acrylic resin, but is not limited to this, and polyethylene, polypropylene, polystyrene, polyurethane, polyvinyl chloride, polyvinyl acetate, ABS resin, AS resin, PET resin, etc. EVA resin, fluororesin, polyamide, polyacetal, polycarbonate, polyphenylene ether, polyester, polyolefin, polyphenylensulfide, polytetrafluoroethylene, polysulfone, polyether sulfone, amorphous polyarylate, liquid crystal polymer, polyether ether ketone, polyimide, Examples thereof include polypropyleneimide (so-called thermoplastic resin). Further, phenol resin, epoxy resin, melamine resin, urea resin, alkyd resin, polyurethane and the like (so-called thermosetting resin) may 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 holes 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 a partially provided one such as a support, but may be provided in an endless frame shape. Further, the shape of the protrusion 15 is not limited to the crosspiece 15a and the cylinder, but may be a polygon such as a rhombus or a hexagon or an ellipse. Further, in these shapes, as shown in FIG. 12, an elongated shape and / or a shape having rounded corners is preferable. By aligning the longitudinal direction and the major axis direction of these shapes in a fixed direction in this way, for example, when cleaning the back surface of the mask 1, the cleaning means (cloth, sponge, etc.) is caught by the protrusions 15. It is possible to eliminate the possibility of damage to the protrusions 15 and the protrusions 15 as much as possible, and it is possible to clean the protrusions smoothly. Therefore, it is desirable to align all the longitudinal directions and the major axis directions of the protrusions 15 in one direction. It should be noted that the elongated shape is limited to the lower end surface (tip surface) of the protrusion 15, and the surface of the root portion 15b of the protrusion 15 does not necessarily have to be elongated in terms of strength and the like.

Further, in each of the above embodiments, the thicknesses of the coating layers 50 and 70 may be different between the inner surface of the through hole 12 and the surfaces of the mask body 10 and the protrusion 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 surfaces of the mask body 10 and the protrusion 15 is T2 (see FIG. 9), T1> T2. For example, it is possible to more reliably prevent the flux from adhering to the inner surface of the through hole 12, which causes a mounting failure of the solder ball. Further, if the coating layer 50 is made of a slippery material (less friction), it will appear as a slippery region 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, and the thickness of T1. The thicker the area, the larger the area. Therefore, when the solder balls 2 are brushed with a squeegee brush, the squeegee brush and the solder balls 2 can be smoothly moved, which is expected to improve productivity and work efficiency. If T1 <T2, when the protrusion 15 is separately formed on the lower surface of the mask body 10, the protrusion 15 can be more reliably prevented from falling off, deforming, or being damaged. There are various methods for forming the coating layer 50, such as a dipping method and a spraying method. When forming the coating layer 50, it is preferable to cover a portion other than the desired forming portion with a protective sheet. Further, when the coating layer 50 is to be formed thick, the portion to be thickened is locally sprayed, or the direction in which the mask 1 is immersed is different (for example, when the coating layer 50 is to be thickened on the lower surface of the mask body 10, the lower surface of the mask body 10 is formed. It is preferable to immerse the mask in a state where the surface and the immersion surface are parallel to each other, and when it is desired to make the inner surface of the through hole 12 thicker, it is preferable to immerse the mask body 10 in a state where the lower surface and the immersion surface are perpendicular to each other).

1 Mask 2 Solder ball 3 Work 6 Electrode 10 Mask body 12 Through hole 15 Protrusion 15a Rail 15b Strut 15c Strut 15'Tip 15 "Root 30, 40 Mother mold 31, 36, 43 Photo resist layer (solder resist layer)
34, 41 Primary pattern resist 34a, 41a Resist 35, 42 Primary electrodeposition layer 38, 44, 60 Secondary pattern resist 38a, 44a Resist 39 Secondary electrodeposition layer 50, 70 Coating layer

Claims (5)

An arrangement mask in which the solder balls (2) are mounted at predetermined positions on the work (3) by transferring the solder balls (2) into the through holes (12) corresponding to the predetermined arrangement pattern.
A mask body (10) having a large number of through holes (12) and a protrusion (15) provided on the opposite surface side of the mask body (10) to the work (3) are provided.
An array mask characterized in that a coating layer made of a water-repellent material is provided at least on the squeegee surface side of the mask body (10). The array mask according to claim 1, wherein the coating layer is formed of a fluororesin, a silicon resin, an emulsion, a resist, or an acrylic resin. The array mask according to claim 1 or 2, wherein the tip end portion (15') of the protrusion portion (15) is formed in an arc shape. According to any one of claims 1 to 3, the protrusion (15) is formed in a tapered shape that narrows downward or a taper that widens downward. The described array mask. The array mask according to any one of claims 1 to 4, wherein the coating layer is provided on the side facing the work (3).

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