JP6508975B2 - Array mask and method of manufacturing the same - Google Patents

Description

  The present invention relates to an alignment mask and a method of manufacturing the same, which are used, for example, to form solder bumps.

  As a method of forming solder bumps, a printing step of applying a flux to electrodes on a workpiece such as a wafer, a flexible substrate, a rigid substrate, an arranging step of arranging solder balls on the flux, and heating for melting and melting the solder balls Through the process, bumps are formed. Then, as a method of arranging the solder balls on the work in the above-described arranging process, there is a transfer method using a mask. In the transfer method, the solder balls are processed using an alignment mask (hereinafter simply referred to as “mask” as appropriate) having positioning through holes through which the solder balls can be inserted corresponding to the alignment pattern of the electrodes of the work. It is mounted on the electrode of. Specifically, after aligning the mask 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. Insert the solder balls one by one. Then, by fixing the solder balls to the flux, the solder balls are temporarily mounted at predetermined positions on the work.

  Such a mask is disclosed in Patent Document 1. In the mask described in Patent Document 1, a large number of supporting protrusions are provided on the lower surface of a mask main body having through holes, and the protruding dimensions of the protrusions are set to the same size. As a result, when the mask is installed on the work, the lower ends of all the supporting projections come in contact with the upper surface of the work, and the opposing gap between the mask main body having the through holes and the work is secured. ing.

JP, 2006-287215, A

  However, in recent years, with the miniaturization of electronic devices, the miniaturization of bumps has progressed. That is, with the miniaturization of the bumps, the through hole spacing dimension and the pattern area spacing dimension in the mask become narrow, and the external dimensions of the protrusions themselves disposed between the through holes and between the pattern areas (the pattern area outer periphery) also become smaller. Due to the tendency, the facing distance between the mask and the work is narrowed, and the flux disposed on the electrode of the work tends to adhere to the mask. In particular, if the flux adheres to the lower surface of the mask main body or the inner surface of the through hole, a mounting failure of the solder ball is likely to occur. An object of the present invention is to provide a mask for alignment that can mount solder balls without defects even when the external dimensions of the protrusions themselves are reduced as the bumps are miniaturized, and a method of manufacturing the same.

  The present invention is an arrangement mask for mounting the solder balls 2 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 comprising the through holes 12 A mask main body 10 in which a large number of regions are formed, and a projection 15 provided on the opposite surface side of the mask main body 10 to the work 3, and at least the coating layer 50 is formed on the lower surface of the mask main body 10 It features. Further, the mask body 10 and the projection 15 are formed separately. In addition, the coating layer 50 is formed to cover the lower surface of the mask body 10 and the surface of the protrusion 15. The coating layer 50 may be formed to a thickness of 1 μm or less.

  Further, the present invention comprises a mask main body 10 in which a large number of pattern areas consisting of through holes 12 are formed, and a projection 15 provided on the side opposite to the work 3 of mask main body 10. The method is a method of manufacturing an alignment mask on which the coating layer 50 is formed. First, a primary pattern resist 41 having a resist body 41 a is formed on a mother die 40. Next, the primary electrodeposition layer 42 is formed on the matrix 40 using the resist body 41 a. Next, on the primary electrodeposition layer 42, a secondary pattern resist 44 having a resist body 44a is formed. 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 which the secondary pattern resist 44 is formed and on the surface of the secondary pattern resist 44.

  According to the alignment mask 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 in which the flux remains attached to the lower surface of the mask main body. In addition, by forming a coating layer so as to cover the lower surface of the mask main body and the surface of the protrusion, the coating layer functions as a protective layer for the protrusion and prevents the protrusion from falling off, deforming, or breaking. it can.

It is a perspective view which shows the whole structure of the mask for arrangement | positioning of this invention, and a workpiece | work. It is a longitudinal cross-sectional side view of the mask for arrangement | sequence which concerns on 1st Embodiment of this invention. It is a top view of the mask for arrangement | sequence which concerns on 1st Embodiment of this invention. It is a longitudinal cross-sectional view of another embodiment of the mask for arrangement | sequence which concerns on 1st Embodiment of this invention. It is a top view of another embodiment of the mask for arrangement | sequence which concerns on 1st Embodiment of this invention. It is a longitudinal cross-sectional view of another embodiment of the mask for arrangement | sequence which concerns on 1st Embodiment of this invention. It is explanatory drawing of the manufacturing method of the mask for arrangement | sequences which concerns on 1st Embodiment of this invention. It is explanatory drawing of the manufacturing method of the mask for arrangement | sequences which concerns on 1st Embodiment of this invention. It is a longitudinal cross-sectional side view 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 | sequences which concerns on 2nd Embodiment of this invention. It is explanatory drawing of the manufacturing method of the mask for arrangement | sequences which concerns on 2nd Embodiment of this invention. FIG. 10 is a partially enlarged plan view of an alignment mask according to another embodiment of the present invention. It is a partial expansion vertical side view of another embodiment of the mask for arrangement | sequence which concerns on 2nd Embodiment of this invention. It is explanatory drawing of the manufacturing method of another embodiment of the mask for arrangement | sequence which concerns on 2nd Embodiment of this invention.

First Embodiment
1 to 3 show a mask for aligning solder balls according to a first embodiment of the present invention. The alignment mask (hereinafter simply referred to as a mask) 1 is to be used in an alignment process of the solder balls 2 in forming the solder bumps. In FIG. 2, reference numeral 3 denotes a workpiece on which the solder ball 2 is to be mounted by the mask 1. The workpiece 3 is, for example, a plurality of semiconductor chips 5 mounted on a base 4 of a glass epoxy substrate, wired by wire bonding and then transfer molded and sealed, and the workpiece is surrounded by the semiconductor chip 5. An electrode 6 which is an input / output terminal is formed in a predetermined pattern on the upper surface of the electrode 3. The work 3 is cut into individual pieces after the formation of the bumps to form individual LSI chips.

  As shown in FIG. 1, the mask 1 is composed of a mask main body 10 made of a nickel alloy such as nickel or nickel cobalt, copper or another metal as a material, and a frame body surrounding the mask main body 10 11 can be worn. At the central portion of the surface of the mask main body 10, a large number of pattern areas consisting of many independent through holes 12 for inserting the solder balls 2 are formed corresponding to the respective semiconductor chips 5. As shown in FIG. 2, the through holes 12 correspond to the arrangement pattern corresponding to the arrangement position of the electrodes 6 of each semiconductor chip 5 on the work 3. The solder balls 2 have a radial dimension of 50 μm or less, and accordingly, the respective through holes 12 are formed in a circular shape in plan view having an inner diameter dimension slightly larger than the radial dimension of the balls 2. There is.

  The frame 11 is a flat plate made of a material such as aluminum, 42 alloy, invar material, SUS430, etc., and is provided with one square-shaped opening corresponding to the mask main body 10 at the center of the surface thereof. A single mask body 10 is held by a single frame 11. The frame body 11 is a molded product having a thickness larger than that of the mask main body 10, and is joined to the outer peripheral edge of the mask main body 10 in an integral manner. 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 the present embodiment. The thickness of the mask body 10 is preferably 10 μm or more, and is set to 200 μm in the present embodiment.

  On the lower surface side of the mask main body 10 (the mask 1), that is, the opposite surface side to the workpiece 3, a protruding portion 15 may be provided in a downwardly protruding shape. Specifically, as shown in FIG. 2 and FIG. 3, the projection 15 (crosspiece 15a) can be provided between the pattern areas (the outer periphery of the pattern area) so as to surround the pattern area. The projections 15 (crosspieces 15a) may not be provided continuously as shown in FIG. 3, but may be provided in fragments. Further, as shown in FIG. 4, the protrusion 15 (the support 15 b) can be provided at a position where the through hole 12 is not formed in the pattern area. Moreover, as a shape of the projection part 15 provided so that a pattern area may be enclosed between adjacent pattern areas (periphery of a pattern area), it may be a support 15c as shown in FIG. If the projection 15 is provided, the facing gap between the mask main body 10 and the work 3 can be secured by being in contact with the upper surface of the work 3 at the time of the arrangement operation. In each of the protrusions 15 (the crosspieces 15a and the columns 15b), as shown in FIGS. 3 and 5, it is formed so as to be tapered toward the tip of the protrusion 15 from the lower surface of the mask main body 10. Preferably, it has a truncated cone shape.

  In addition, as shown in FIG. 6, as the shape of the protrusion 15, as shown in FIG. 6, a diverging shape (the diameter of the protrusion 15 increases from the root to the tip of the protrusion 15). It may be an end-to-end 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 particularly on the root portion 15 ′ ′ of the projection 15, and even when the flux 17 adheres to the projection 15 when the mask 1 is placed on the work 3. Since the side surfaces of the protrusions 15 are arcs, it is possible to prevent the flux 17 from coming around the through hole 12, so that the mounting defect of the solder ball 2 due to the flux 17 adhering to the through hole 12 may be caused. The end position of the root portion 15 ′ ′ of the projection 15 is preferably located in the vicinity of the through hole 12 on the lower surface of the mask main body 10, and the lower surface 10a of the mask main body and the inner surface 12a of the through hole It is possible to consider an embodiment in which it is located at the intersection of the two, and an embodiment in which it is located at a space from the through hole 12 on the mask main body lower surface 10a. Further, the side surface of the projection 15 may be either a convex arc or a concave arc, and if it is a convex arc, the strength is good, and if it is a concave arc, the flux 17 is at any position on the side of the projection 15 There may be no part approaching the attached electrode 6, that is, a state in which a certain distance is kept from the electrode 6 to which the flux 17 is attached. Furthermore, the tip 15 'and / or the root 15' 'of the projection 15 may be formed in an arc shape, whereby the risk of the flux 17 adhering to the projection 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 main body 10 is preferably 2: 1 or more, and the thickness of the mask main body 10 satisfies this within a range of 10 to 300 μm. Is more preferred. The projection 15 preferably has a large aspect ratio (the ratio of the height of the projection 15 to the tip size), and in the present embodiment, the aspect ratio is 3. The root 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 in the present embodiment. Furthermore, 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 be 1: 1.2 to 1.4 or more. Furthermore, it is preferable to set the dimension L4 from the pattern area to the root of the protrusion 15 (the crosspiece 15a, the support 15c (described later), the protrusion 15d (described later)) to 0.01 mm or more. It is assumed to be 02 mm. Such conditions can prevent the adhesion of the flux as much as possible. At this time, the relationship between the ratio of the tip dimension L1 of the protrusion 15 to the root dimension L2 and the relationship of the dimension L4 from the pattern area to the root of the protrusion 15 are satisfied to prevent breakage of the protrusion 15 and flux It is possible to achieve both adhesion prevention. Furthermore, when the dimension from the pattern area to the center of the tip of the protrusion 15 (the crosspiece 15a, the support 15c (described later), and the protrusion 15d (described later)) is L5, the ratio of L1 to L2 to L5 is 1 to 3 By setting the ratio to 2.5 or more, it is possible to make the best use of the above compatible effects.

  Here, the mask body 10 and the projection 15 are integrally formed as the mask 1. However, the mask body 10 and the projection 15 may be integrally formed of separate members. This is because if the mask main body 10 is formed of a magnetic material and the protrusions 15 are formed of a nonmagnetic material in the mask 1 described above, the mask 1 is fixed to the workpiece 3 by magnetic attraction of a magnet. Since the magnetic force can be exerted uniformly, there is no risk of the mask 1 being bent carelessly, and the mask 1 can be made to adhere well to the work, and the positioning accuracy of the through hole 12 with respect to the electrode 6 can be improved. In addition, when the mask 1 is removed, the work 3 and the projection 15 are not directly magnetically coupled, so that the plate separation can be improved. The mask 1 can be obtained, for example, by forming the mask main body 10 of magnetic metal (nickel, iron or the like) and forming the protrusion 15 of nonmagnetic metal (copper, aluminum or the like).

  Moreover, in what forms the projection part 15 with a nonmagnetic material, it may be formed not only with the said metal but with resin or a resist. As a result, in addition to the above-mentioned effects, a cushioning action derived from the elasticity of the resin is exhibited, and when the projection 15 abuts on the work 3, the possibility of damage to the work 3 is reduced. In addition, in order to exhibit the effect concerned notably, it is preferable to form not only the projection part 15 but all the parts in contact with the work 3 in the mask 1 with resin. Moreover, when forming the projection part 15 with resin, if it uses the same thing as a resist used when forming the mask main body 10 by an electroforming method, it can form with sufficient productive efficiency.

  Further, in the present mask 1, as shown in FIGS. 2, 4 and 6, the 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 is preferably one having water repellency, and examples of the material thereof include fluorocarbon resin, silicone 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 flux remains attached to the lower surface of the mask main body 10 or the inner surface of the through hole 12 It can prevent. 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 projecting portions 15 (crosspieces 15 a) between the pattern regions. In short, it is desirable to form the solder ball in a portion where mounting defects of the solder ball are likely to occur when the flux adheres, and when the mask 1 is placed on the workpiece, the mask main body 10 facing the flux 17 applied on the electrode 6 And it is desirable to form on the surface of the projection 15.

  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 in each drawing, the thickness size of the mask main body 10 and the like, and the like are shown in such a size for the convenience of drawing preparation. 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. The coating layer 50 is not illustrated in FIGS. 3 and 5.

  The arranging operation of the solder balls 2 using the mask 1 is performed in the following procedure. This arrangement operation is performed by a dedicated arrangement device (see FIG. 1, FIG. 5, etc. of Patent Document 1). First, the flux 17 (see FIG. 2) is applied by printing on the electrode 6 of the work 3. Next, after the mask 1 is aligned on the work 3 so that the through holes 12 and the electrodes 6 coincide with each other, 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 face of the projection 15 abuts on the surface of the work 3 in the fixed state, whereby the mask main body 10 is moved with the work 3 as shown in FIG. 2, FIG. 4 and FIG. The posture is held in the separated posture in which the opposing gap of the two is secured. At this time, a magnet can be disposed below the workpiece 3 and the mask 1 can be attracted to the workpiece 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 ball 2 is adhesively held by the flux 17 in a temporarily fixed manner. In the solder ball 2 loading operation using such a squeegee brush, even if the squeegee brush pressure is largely applied to the mask 1, the projection 15 can prevent the mask 1 from being bent, and the loading operation can proceed smoothly and efficiently. Can.

  As described above, according to the mask 1 according to the present embodiment, since the projection 15 that forms the facing gap between the mask main body 10 and the work 3 is provided, the facing gap with the work 3 can be assured by the projection 15 It is possible to ensure the operation of inserting the solder balls 2 into the through holes 12 efficiently and without leakage.

  The frame 11 for reinforcement can be provided on the outer peripheral edge of the mask main body 10, and if the mask main body 10 is formed in such a tensioned state that the stress in the direction of contracting inward acts on itself, The expansion of the mask body 10 caused by the change in temperature can be absorbed by the tension in the contraction direction. Thereby, the occurrence of positional deviation of the mask body 10 with respect to the work 3 can be prevented. Further, since 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, the manufacturing method of the mask 1 for arrangement | sequence of the structure which concerns is shown in FIG.7 and FIG.8. First, for example, a photoresist layer 31 is formed on the surface of a conductive stainless steel or brass steel base die 30. The photoresist layer 31 is formed by thermocompression bonding by laminating one to several negative-type photosensitive dry photoresists according to a predetermined height. Next, as shown in FIG. 7A, a pattern film (glass mask) 32 having light transmitting holes 32a corresponding to the protrusions 15 is adhered onto the photoresist layer 31, and then ultraviolet light is applied by the ultraviolet light lamp 33. The film is exposed to light, exposed to light, and developed and dried to dissolve and remove the unexposed area, thereby corresponding to the tapered protrusion 15 as shown in FIG. 7B. A primary pattern resist 34 having a resist body 34 a was formed on the mold 30. At this time, it is preferable to make the resist body 34 a tapered by using a photoresist which is hard to transmit ultraviolet light or weakening the exposure amount. Subsequently, the mother die 30 is placed in an electroforming bath prepared under a predetermined condition, and as shown in FIG. 7C, the resist body 34a of the mother die 30 is within the range of the height of the resist body 34a. An electrodeposited metal such as nickel or copper was electroformed on the surface not covered with the above to form a primary electroformed layer 35. Here, the primary electroformed layer 35 was formed over substantially the entire surface of the matrix 30 (first electroforming process). Next, as shown in FIG. 7D, the primary pattern resist 34 is removed. Here, the surface of the primary electroformed layer 35 may be polished.

  Next, as shown in FIG. 8A, a photoresist layer 36 is formed on the entire surface of the primary electroformed layer 35 and the matrix 30, and then the holes 12 are formed on the surface of the photoresist layer 36. After the pattern film (glass mask) 37 having the corresponding light transmission holes 37a is brought into close contact, the ultraviolet light is irradiated by the ultraviolet light lamp 33 to perform exposure, development and drying are performed, and the unexposed area is By dissolving and removing, as shown in FIG. 8 (b), a secondary pattern resist 38 having a resist body 38 a corresponding to the mask main body 10 was formed on the surface of the primary electroformed layer 35. Subsequently, it is placed in an electroforming tank built up under predetermined conditions, and as shown in FIG. 8C, it is covered with the matrix 30 and the resist body 38a within the height range of the resist body 38a. An electrodeposited metal such as nickel or copper was electroformed on the surface of the primary electroformed layer 35 to form a secondary electroformed layer 39 (second electroforming process). Next, the secondary pattern resist 38 is dissolved and removed, and the secondary electroformed layer 39 is peeled off from the matrix 30 and the primary electroformed layer 35. Finally, the coating layer 50 is applied to the surface of the secondary electroformed layer 39 corresponding to the lower surface of the mask main body 10 and the inner surface of the through hole 12 and the secondary pattern resist 38 of the secondary electroformed layer 39. By forming, the mask 1 as shown to FIG. 8 (e) and FIG. 2 was obtained.

  If the frame 11 is attached to the mask 1 thus obtained, an alignment mask 1 as shown in FIG. 1 is obtained. The mask 1 (secondary electroformed layer 39) can be held on the frame 11 in a state in which the mask 1 (second electroformed layer 39) is tensioned such that a stress in a direction in which the mask 1 contracts inward acts. To apply such stress, for example, the frame 11 is attached to the outer peripheral edge of the mask 1 under a high temperature environment using the difference between the thermal expansion coefficients of the frame 11 and the mask 1. It can be realized by contracting inward.

  According to the manufacturing method of the mask 1 as described above, since the mask for alignment can be manufactured with high accuracy using electroforming, the solder balls 2 can be mounted on the work 3 with high positional accuracy. In addition, when the mask 1 having the protrusions 15 is formed integrally with the mask main body 10 and the protrusions 15 by a single electroforming (second electroforming process), the mask main body 10 and the protrusions can be obtained. As compared with the one in which 15 and 15 are separately formed, there is less possibility that inconveniences such as breakage of the protrusion 15 may occur, and it is also excellent in that the mask 1 having excellent reliability can be obtained with high accuracy. In addition, if the protrusion 15 is formed in a tapered shape so as to increase as it gets closer to the lower surface of the mask main body 10, stress concentration on the root of the protrusion 15 in particular is avoided. Since it is possible to abut between the electrodes 6 in a state in which the protrusions 15 are separated from the electrodes 6 to which the flux 17 is applied while being firmly reinforced, solder by the flux 17 applied to the electrodes 6 adhering to the mask main body 10 Improper 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 15 'of the projection 15 to the dimension of the root 15' 'to 1: 3 or more and to set the aspect ratio of the projection 15 to 3 or more. The fabrication of the protrusions 15 having such desired dimensions and aspect ratios can be easily obtained by adjusting the shape of the resist pattern 35.

  In the mask 1 having such a configuration, the through holes 12 and the protrusions 15 may be straight or tapered. Here, specifically describing the case where the through hole 12 and the projection 15 are tapered, the through hole 12 has a tapered shape which is tapered toward the surface of the mask main body 10 facing the work 3. By providing the solder ball 2, the solder ball 2 can easily be drawn into the through hole 12, and by providing a taper in the shape of a forward extension toward the surface of the mask body 10 facing the workpiece 3, the mask body 10 faces the workpiece 3. It can prevent that a flux adheres to the through-hole 12 periphery in the surface side. Further, by providing a tapered shape in the projection 15 toward the surface facing the workpiece 3 of the mask main body 10, the mask 15 can be firmly placed on the workpiece 3. By providing a tapered shape toward the surface facing the workpiece 3 of the mask main body 10, the strength of the protrusion 15 is secured even when the electrodes 6 of the workpiece 3 are arranged at a narrow pitch. However, the abutment of the projection 15 on the workpiece 3 can be firmly dealt with. 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 alignment 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 alignment mask of the present embodiment, since the coating layer 50 is also formed on the surface of the protrusion 15, adhesion of the flux to the protrusion 15 can be prevented. Further, 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 the flux adheres to the inner surface of the through hole 12, the flux is repelled. It can flow on the work through the surface of the projection 15. Moreover, the wraparound of the flux 17 into the through hole 12 can be more reliably prevented.

  Furthermore, by forming the coating layer 50 so as to cover the entire surface of the lower surface of the mask main body 10 and the surface of the protrusion 15, for example, when the mask main body 10 and the protrusion 15 are formed as separate members, It is weak (this means that the through hole spacing dimension and pattern area spacing dimension become narrower as the bumps become finer, and the external dimensions of the protrusions 15 themselves disposed between the through holes and between the pattern areas (pattern area outer periphery) are also smaller (Due to a decrease in the bonding area between the protrusion 15 and the mask body 10)), the protrusion 15 may be inadvertently dropped, deformed or damaged when the mask 1 is used, As a result, the coating layer 50 functions as a protective layer for the protrusions 15, which can also contribute to the prevention of the detachment, deformation, and breakage of the protrusions 15. In addition, in order to specialize in preventing the dropout, deformation, and breakage of the protrusion 15, it is preferable to form the metal layer (Ni, Cu or the like) by sputtering or electroless plating and provide the coating layer 50.

  10 and 11 show a method of manufacturing the alignment mask of this embodiment. First, as shown in FIG. 10A, a mother die 40 is prepared. The mother die 40 may be anything as long as it has conductivity, and stainless steel is used in this embodiment. Next, a photoresist layer is formed on the surface of the mold 40, and exposure, development, and drying processes are performed by a known method to dissolve and remove the unexposed portions, as shown in FIG. A primary pattern resist 41 having a resist body 41 a was formed on a mother die 40. The photoresist layer was formed by laminating one to several negative-type photosensitive dry film resists according to a predetermined height. Next, the mother mold 40 is placed in an electroforming bath prepared under predetermined conditions, and covered with the resist body 41 a of the mother mold 40 to the same extent as the height of the resist body 41 a as shown in FIG. An electrodeposited metal was electroformed on the unexposed surface to form a primary electrodeposited layer 42. In the present embodiment, the primary electrodeposition layer 42 is formed by Ni-Co electroforming. After the formation of the primary electrodeposition layer 42, mechanical polishing such as belt polishing and / or electropolishing is preferably performed on the surface of the primary electrodeposition layer 42. Next, as shown in FIG. 10D, 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. The solder resist layer 43 was formed by laminating one or several sheets in accordance with a predetermined height. Next, each process of exposure, development, and drying is performed to dissolve and remove the unexposed area, whereby the secondary pattern resist 44 having the resist body 44a is formed on the primary electrodeposition layer 42, as shown in FIG. Integrally formed. It is preferable to perform a drop prevention process such as baking after the secondary pattern resist 44 is formed. Thereby, the adhesion between the secondary pattern resist 44 having the resist body 44 a and the primary electrodeposition layer 42 can be made stronger. Next, as shown in FIG. 11C, the primary electrodeposition layer 42 and the secondary pattern resist 44 formed on the surface thereof are peeled off from the matrix 40. Finally, a coating layer 50 is 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 to obtain the alignment mask shown in FIGS. You can get one. The coating layer 50 may be formed before the primary electrodeposition layer 42 and the secondary pattern resist 44 are peeled off from the matrix 40. The coating layer 50 may be formed not only on the surface of the primary electrodeposition layer 42 on the side 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 alignment mask according to the second embodiment will be described. Here, as shown in FIG. 13A, the protrusion 15 is formed of a resin, and the coating layer 70 is formed on the surface of the protrusion 15 as a material of the coating layer 70. The material of the projection 15 is different from that of the material.

  As described above, this mask is used to mount the solder balls on the electrodes of the work, but dirt and the like may be attached to the mask during the solder ball arranging process (transfer mounting). Clean the mask as needed to remove it. When cleaning the mask, since the solvent is used, the solvent may cause an adverse effect such as stickiness on the surface of the material constituting the projection, but since the surface of the projection has a coating layer, It protects from such an adverse effect.

  Therefore, in the mask of the present embodiment, the coating layer 70 is formed on the surface of the mask 15 in order to prevent an adverse effect on the protrusions 15 formed of resin, and the material (resin) in which the coating layer 70 constitutes the protrusions 15 And made of a different material. The coating layer 70 can be formed of, for example, a photosensitive material containing an acrylic resin as a main component, in addition to the above materials.

  The manufacturing method of the mask for alignment is the same as the above-mentioned process (see FIG. 10) from the preparation of the matrix 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 formed integrally 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-developable photosensitive material, and the main components are acrylic resin (55 to 65%), barium sulfate (15 to 25%), and silicon dioxide (15 to 25%). Finally, the primary electrodeposition layer 42 from the matrix 40 is peeled off together with the secondary pattern resist 60 and the coating layer 70 formed on the surface thereof, whereby the alignment mask 1 shown in FIG. 14C and FIG. 13 is obtained. You can get it. 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, after forming the secondary pattern resist 60 on the primary electrodeposition layer 42, the coating layer 70 may be formed after peeling off from the matrix 40. In this way, 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 be formed on the inner wall of the through hole 12 as well. In addition, after the secondary pattern resist 60 and the coating layer 70 are formed, it is preferable to perform a drop prevention process 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. The dropout prevention process may be performed each time the secondary pattern resist 60 and the coating layer 70 are formed, or may be performed after forming the coating layer 70 on the surface of the secondary pattern resist 60.

  The mask 1 obtained by the manufacturing method concerned becomes strong to washing (solvent), and it can prevent that stickiness occurs to projection 15 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 projection 15, damage or omission of the projection 15 can be prevented.

  Here, since the protrusion 15 and the coating layer 70 are 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 main body 10 (the protrusion 15 Before the coating layer 70 is formed on the surface of the projection 15), the projections 15 are washed to get sticky on the surface of the projections 15, and the coating layer 70 is formed on the surface thereof, thereby forming the projections 15 and the coating layer. The adhesion to 70 can be made stronger.

  Further, as shown in FIG. 13C, the protrusions 15 can be formed only of the material for forming the coating layer 70. The material which forms the coating layer 70 is a thing which a flux does not adhere easily, and, specifically, the resin mixture in which barium sulfate and / or silicon dioxide were contained in the acrylic resin is mentioned. This resin mixture is excellent in solvent resistance. This will be specifically described. The width 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 provided on the mask body made of nickel-cobalt alloy with a cleaning agent (manufactured by Kaken Tech Co., Ltd.) for 6 to 24 hours (6 hours, 12 hours, 24 hours) Although it was immersed 3 times, it could be confirmed that there was no peeling of the protrusions in all the masks. Furthermore, since the resin mixture concerned has good compatibility with the mask main body 10 and good adhesion, it is possible to narrow the width dimension of the protrusion 15. Since the resin mixture concerned has hardness (5H to 6H in scratch hardness test according to JIS standard), if the width dimension of the projection is larger than 5 mm when the thickness of the mask main body is 100 μm or less, the mask warps. It is preferable that the width dimension of the projection be 5 mm or less because there is a risk of Thus, the coating layer 70 is formed mainly of a material such as a fluorocarbon resin, a silicon resin, an acrylic resin, or the like. And it is possible to constitute projection part 15 by having the quality of the material concerned as a main component.

  The main component of the resin mixture for forming the protrusion 15 is acrylic resin, but not limited to this, polyethylene, polypropylene, polystyrene, polyurethane, polyvinyl chloride, polyvinyl acetate, ABS resin, AS resin, PET resin, EVA resin, fluorocarbon resin, polyamide, polyacetal, polycarbonate, polyphenylene ether, polyester, polyolefin, polyphenylene sulfide, polytetrafluoroethylene, polysulfone, polyether sulfone, amorphous polyarylate, liquid crystal polymer, polyether ether ketone, polyimide, Polyamide imide etc. (so-called, thermoplastic resin) are mentioned. In addition, 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-described embodiments, the protrusions 15 (posts 15b) and the through holes 12 may be arranged such that the protrusions 15 (posts 15b) surround 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 disposed so as to surround one through hole 12, the shape of the protrusions 15 is not limited to that provided partially like a support, but may be provided in an endless frame shape. Further, the shape of the projection 15 is not limited to the crosspiece 15a or the cylinder, but may be a polygon such as a rhombus or a hexagon or an ellipse. Furthermore, in these shapes, as shown in FIG. 10, it is preferable to have an elongated shape and / or rounded corners. Thus, by aligning the longitudinal direction and major axis direction of these shapes with a fixed direction, for example, when cleaning the back surface of the mask 1, cleaning means (cloth, sponge, etc.) may be caught by the protrusion 15. As a result, the risk of breakage of the projections 15 can be eliminated as much as possible, and smooth cleaning can be achieved. Therefore, it is desirable to match the longitudinal direction and the major axis direction of all the protrusions 15 in one direction. The elongated shape is at the lower end surface (tip surface) of the protrusion 15 and the surface of the root portion 15 b of the protrusion 15 is not necessarily elongated in view of strength and the like.

  In each of the above embodiments, the thickness of the coating layers 50 and 70 may be made different between the inner surface of the through hole 12 and the surface of the mask main 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 main body 10 and the protrusion 15 is T2 (see FIG. 9), T1> T2. For example, it is possible to more reliably prevent the adhesion of the flux to the inner surface of the through hole 12 which causes mounting failure of the solder ball. Further, if the coating layer 50 is formed of a slippery (small friction) material, it will appear as a slippery area 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 thickness is, the larger the area becomes. Therefore, when the solder ball 2 is scratched with a squeegee brush, the squeegee brush or the solder ball 2 can be moved smoothly, and improvement in productivity and work efficiency can be expected. And if T1 <T2, when the projection 15 is separately formed on the lower surface of the mask main body 10, it is possible to prevent the falling off, the deformation, and the breakage of the projection 15 more reliably. In addition, although there exist various methods, such as a dip coating method and a spray method, as a formation method of this coating layer 50, when forming the coating layer 50, it is good to cover parts other than the formation part to desire with a protective sheet. 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 made different (for example, when it is desired to thicken the lower surface of the mask main body 10, the lower surface of the mask main body 10) If it is desirable to make the inner surface of the through hole 12 thicker, it is better to immerse the lower surface of the mask body 10 and the immersion surface in a vertical state).

DESCRIPTION OF SYMBOLS 1 mask 2 solder ball 3 work 6 electrode 10 mask main body 12 through-hole 15 protrusion 15a crosspiece 15b post 15c post 15c convex part 15 'tip 15 "root part 30, 40 matrix 31, 36, 43 photoresist layer (solder Resist layer)
34, 41 primary pattern resist 34a, 41a resist body 35, 42 primary electrodeposited layer 38, 44, 60 secondary pattern resist 38a, 44a resist body 39 secondary electrodeposited layer 50, 70 coating layer

Claims (6)

An alignment mask which mounts the solder ball (2) at a predetermined position on a work (3) by transferring the solder ball (2) into the through holes (12) corresponding to the predetermined arrangement pattern,
A mask main body (10) in which a large number of pattern areas consisting of the through holes (12) are formed, and a projection (15) provided on the side of the mask main body (10) facing the work (3) Equipped
Before SL mask body (10) lower surface, said projections (15) surface, and the through hole (12) inner surface, a coating layer can prevent flux attachment (50) for sequence, characterized in that is formed mask.   The mask for alignment according to claim 1, wherein the mask body (10) and the projection (15) are separately formed. The coating layer (50), the sequence mask according to claim 1 or 2, characterized in that it is formed in the mask body (10) upper surface.   The alignment mask according to any one of claims 1 to 3, wherein the coating layer (50) is formed with a thickness of 1 μm or less. The mask main body (10) in which a large number of pattern areas consisting of through holes (12) are formed, and a projection (15) provided on the side of the mask main body (10) facing the workpiece (3) before SL mask body (10) lower surface, said projections (15) surface, and the through hole (12) inner surface, a method of manufacturing the array mask coating layer can prevent flux attachment (50) is formed ,
Forming a primary pattern resist (41) having a resist body (41a) on a matrix (40);
Forming a primary electrodeposition layer (42) on the matrix (40) using the resist body (41a);
Removing the primary pattern resist (41);
Forming a secondary pattern resist (44) having a resist body (44a) on the primary electrodeposition layer (42);
The surface of the primary electrodeposition layer (42) on which the secondary pattern resist (44) is formed, the surface of the secondary pattern resist (44), and the resist body of the primary electrodeposition layer (42) Forming the coating layer (50) on the surface which has been in contact with 41a) . In the step of forming the coating layer (50), the coating layer (50) is formed on the surface of the primary electrodeposition layer (42) opposite to the side on which the secondary pattern resist (44) is formed. The method for manufacturing an alignment mask according to claim 5, wherein