JP2018041984A - Array mask and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an array mask that can cope with even when outer dimensions of a protrusion itself are made smaller accompanied with miniaturization of a bump.SOLUTION: An array mask for placing solder balls 2 at predetermined positions on a work-piece 3 by feeding the solder ball 2 into a through-hole 12 corresponding to a predetermined array pattern, includes: a mask body 10 which has many pattern regions constituted of through-holes 12 formed thereon; and a projection 15 formed on a lower face of the mask body 10. A coating layer is formed on at least a pattern region in the lower face of the mask body 10.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an array mask used for forming, for example, solder bumps and a method for manufacturing the same.

  The solder bump formation method includes a printing process in which a flux is applied to electrodes on a workpiece such as a wafer, a flexible substrate, and a rigid substrate, 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. And in the above-mentioned arrangement | positioning process, there exists a transfer system using a mask as a system which arranges a solder ball on a workpiece | work. In the transfer method, a solder ball is placed on a work piece using an arrangement mask (hereinafter, simply referred to as “mask” as appropriate) having a positioning through hole through which a solder ball can be inserted corresponding to the arrangement pattern of the work electrode. It is mounted on the electrode. Specifically, after aligning the mask with respect to the workpiece so that the through hole and the electrode coincide with each other, the solder balls supplied on the mask are swept with a squeegee or a brush so that each through hole is aligned. 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 workpiece.

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

JP 2006-287215 A

  However, in recent years, bumps have been miniaturized along with miniaturization of electronic devices. That is, with the miniaturization of the bumps, the through hole dimension and the pattern area interval dimension in the mask become narrower, and the external dimensions of the projections arranged between the through holes and between the pattern areas (outer periphery of the pattern area) also become smaller. Because of this tendency, the facing distance between the mask and the workpiece is narrowed, and the flux arranged on the workpiece electrode is likely 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, poor solder ball mounting is likely to occur. SUMMARY OF THE INVENTION An object of the present invention is to provide an array mask that can mount solder balls without defects even when the external dimensions of the projections themselves are reduced with the miniaturization of bumps, and a method for manufacturing the same.

  The present invention is an array mask in which the solder balls 2 are mounted at predetermined positions on the work 3 by swinging the solder balls 2 into the through holes 12 corresponding to the predetermined array pattern. A mask body 10 in which a large number of regions are formed, and a protrusion 15 provided on the surface of the mask body 10 facing the workpiece 3, and a coating layer 50 is formed on at least the lower surface of the mask body 10. Features. Further, the mask body 10 and the protrusion 15 are formed separately. The coating layer 50 is formed so as to cover the lower surface of the mask main body 10 and the surface of the protrusion 15. The coating layer 50 is preferably formed with a thickness of 1 μm or less.

  The present invention also includes a mask main body 10 in which a large number of pattern regions each including the through-holes 12 are formed, and a protrusion 15 provided on the surface of the mask main body 10 facing the workpiece 3, at least on the lower surface of the mask main body 10. This is a method for manufacturing an alignment mask in which the coating layer 50 is formed. First, a primary pattern resist 41 having a resist body 41 a is formed on the mother die 40. Next, the primary electrodeposition layer 42 is formed on the mother die 40 using the resist body 41a. Next, a secondary pattern resist 44 having a resist body 44 a is formed on the primary electrodeposition layer 42. Next, the coating layer 50 is formed on the surface of the primary electrodeposition layer 42. The coating layer 50 is preferably formed on the surface of the primary electrodeposition layer 42 on the side having the secondary pattern resist 44 and the surface of the secondary pattern resist 44.

  According to the arrangement mask of the present invention, since the coating layer is formed on the lower surface of the mask body, it is possible to prevent the state in which the flux remains attached to the lower surface of the mask body. In addition, by forming a coating layer so as to cover the lower surface of the mask body and the surface of the protrusion, the coating layer functions as a protective layer for the protrusion, and prevents the protrusion from dropping, deforming, or damaging. it can.

It is a perspective view which shows the whole structure of the mask for arrangement | sequence of this invention, and a workpiece | work. It is a vertical 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 vertical side 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 concerning the 1st embodiment of the present invention. It is a vertical side 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 | sequence which concerns on 1st Embodiment of this invention. It is explanatory drawing of the manufacturing method of the mask for arrangement | sequence which concerns on 1st Embodiment of this invention. It is a vertical 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 | sequence which concerns on 2nd Embodiment of this invention. It is explanatory drawing of the manufacturing method of the mask for arrangement | sequence which concerns on 2nd Embodiment of this invention. It is the elements on larger scale of the arrangement | sequence mask which concerns on another embodiment of this invention. It is a partial expanded 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 | sequences concerning 2nd Embodiment of this invention.

(First embodiment)
1 to 3 show a solder ball arrangement mask according to the first embodiment of the present invention. This arrangement mask (hereinafter simply referred to as a mask) 1 is used in the arrangement process of the solder balls 2 in the formation of solder bumps. In FIG. 2, reference numeral 3 indicates a work to be mounted with the solder ball 2 by the mask 1. For example, the work 3 is formed by mounting a plurality of semiconductor chips 5 on a base 4 of a glass epoxy substrate, wiring by wire bonding, and sealing with a transfer mold. 3 is formed with an electrode 6 as an input / output terminal 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 main body 10 made of a nickel alloy such as nickel or nickel cobalt, copper or other metal as a raw material, and the mask main body 10 surrounds the frame body. 11 can be mounted. In the center of the board surface of the mask main body 10, a large number of pattern regions each including a large number of independent through holes 12 for inserting the solder balls 2 are formed corresponding to the respective semiconductor chips 5. As shown in FIG. 2, the through holes 12 correspond to an arrangement pattern corresponding to the arrangement positions of the electrodes 6 of the respective semiconductor chips 5 on the workpiece 3. The solder ball 2 has a radial dimension of 50 μm or less, and in accordance with this, each through hole 12 is formed in a circular shape in plan view having an inner diameter dimension slightly larger than the radial dimension of the ball 2. Yes.

  The frame 11 is a flat plate made of a material such as aluminum, 42 alloy, Invar, SUS430, etc., and has a single rectangular opening corresponding to the mask body 10 at the center of the board surface. A single mask body 10 is held by a single frame 11. The frame 11 is a molded product that is thicker than the mask body 10, and is integrally and integrally joined to the outer peripheral edge of the mask body 10. Here, the thickness dimension of the frame 11 is set to, 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 this embodiment.

  On the lower surface side of the mask main body 10 (mask 1), that is, the surface facing the workpiece 3, a protruding portion 15 that protrudes downward can be provided. Specifically, as shown in FIGS. 2 and 3, a protrusion 15 (crosspiece 15 a) can be provided between the pattern areas (outer periphery of the pattern areas) so as to surround the pattern areas. This protrusion 15 (crosspiece 15a) may not be provided continuously as shown in FIG. 3, but may be provided in pieces. Moreover, as shown in FIG. 4, the protrusion part 15 (support | pillar 15b) can be provided in the position in which the through-hole 12 in the pattern area | region is not formed. Further, the shape of the protrusion 15 provided so as to surround the pattern region between adjacent pattern regions (outer periphery of the pattern region) is not limited to the crosspiece 15a, but may be a support column 15c as shown in FIG. If the projecting portion 15 is provided, it is possible to secure a facing gap between the mask main body 10 and the workpiece 3 by contacting the upper surface of the workpiece 3 during the arraying operation. As shown in FIGS. 2 and 4, each protrusion 15 (crosspiece 15 a and column 15 b) is formed so as to be tapered 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 (squeezed from the root of the protrusion 15 toward the tip). It may be a constricted shape), and the side surface may be formed in an arc shape. This can prevent damage caused by concentration of stress on the projection 15, particularly the root portion 15 ″, and even if the flux 17 adheres to the projection 15 when the mask 1 is placed on the workpiece 3. Since the side surface of the protrusion 15 is an arc, the flux 17 can be prevented from wrapping around the through hole 12, which may cause a mounting failure of the solder ball 2 due to the flux 17 adhering to the through hole 12. It should be noted that the end position of the base portion 15 ″ of the protrusion 15 is preferably located in the vicinity of the through hole 12 on the lower surface of the mask main body 10, and the mask main body lower surface 10a, the through hole inner surface 12a, and the like. A form located at the intersection of the two and a form located at a position where a gap is formed from the through hole 12 on the lower surface 10a of the mask main body are conceivable. 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 will be good, and if it is a concave arc, the flux 17 will be at any position on the side of the projection 15. There may be no portion approaching the attached electrode 6, that is, a state where a certain distance is maintained from the electrode 6 to which the flux 17 is attached. Furthermore, the tip portion 15 ′ and / or the root portion 15 ″ of the protrusion 15 may be formed in an arc shape, thereby reducing the possibility that the flux 17 adheres to the protrusion 15 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 to 1 or more, and this is satisfied when the thickness of the mask body 10 is in the range of 10 to 300 μm. It is more preferable. The protrusion 15 preferably has a large aspect ratio (ratio between the height of the protrusion 15 and the tip dimension), and the aspect ratio is 3 in this embodiment. 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. Furthermore, the ratio of the tip dimension L1, the root dimension L2, and the width dimension L3 between the through holes 12 of the protrusion 15 is preferably 1: 1 to 1.2 to 1.4 or more. Furthermore, it is preferable to set the dimension L4 from the pattern region to the base of the protrusion 15 (the crosspiece 15a and the support column 15c) to 0.01 mm or more, and in this embodiment, 0.02 mm. Under such conditions, adhesion of flux can be prevented as much as possible. At this time, by satisfying the relationship of the ratio between the tip dimension L1 and the root dimension L2 of the projection 15 and the dimension L4 from the pattern region to the root of the projection 15, the damage prevention of the projection 15 and the flux are achieved. It is possible to achieve both prevention of adhesion. Furthermore, when the dimension from the pattern area to the center of the tip of the protrusion 15 (the crosspiece 15a, the support column 15c) is L5, the ratio of L1, L2, and L5 is 1: 3 to 2.5 or more, The above-mentioned compatibility effect can be utilized to the maximum.

  Here, the mask 1 is formed by integrating the mask body 10 and the protrusion 15, but the mask body 10 and the protrusion 15 may be integrally formed by separate members. In the mask 1, if the mask body 10 is formed of a magnetic material and the protrusion 15 is formed of a non-magnetic material, the mask 1 is fixed to the work 1 when the mask 1 is fixed to the work 3 by magnetic attraction of a magnet. Since the magnetic force can be applied uniformly, the mask 1 is not inadvertently bent and can be satisfactorily adhered to 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 workpiece 3 and the protrusion 15 are not directly magnetically coupled, so that the plate separation can be improved. Such a mask 1 can be obtained, for example, by forming the mask body 10 from a magnetic metal (nickel, iron, etc.) and forming the protrusion 15 from a nonmagnetic metal (copper, aluminum, etc.).

  Moreover, what forms the projection part 15 with a nonmagnetic material is not limited to the above metal, but may be formed of resin or resist. Thereby, in addition to the above effects, a cushioning action derived from the elasticity of the resin is exhibited, and the possibility that the work 3 is damaged when the protrusion 15 contacts the work 3 is reduced. In addition, in order to show such an effect remarkably, it is preferable to form not only the projection part 15 but all the parts contact | abutted with the workpiece | work 3 in the mask 1 with resin. Moreover, when forming the projection part 15 with resin, if the same resist as that used when forming the mask body 10 by electroforming is used, it can be formed with high production efficiency.

  Moreover, in this mask 1, as shown in FIG.2, FIG.4, FIG.6, the coating layer 50 is provided in the mask main body 10 lower surface and the through-hole 12 inner surface. The coating layer 50 preferably has water repellency, and examples of the material include a fluororesin, a silicon resin, an emulsion, and a 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 body 10 and the inner surface of the through hole 12, and the flux remains attached to the lower surface of the mask body 10 and the inner surface of the through hole 12. Can be prevented. The coating layer 50 may be formed on the upper surface of the mask body 10 or may not be formed on the lower surface of the mask body 10 between the pattern regions and between the protrusions 15 (the crosspieces 15a and the support columns 15c). . In short, it is desirable to form the solder ball on the part where defective mounting of the solder ball is likely to occur when the flux adheres, and when the mask 1 is placed on the work, the mask body 10 facing the flux 17 applied on the electrode 6. And it is desirable to form on the surface of the protrusion 15.

  Each drawing does not show the actual state of the mask 1 but schematically shows it. In addition, the opening dimension of the through-hole 12 and the thickness dimension of the mask body 10 and the like in each drawing are shown in such dimensions for the convenience of drawing. 3 and 5, what is indicated 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. 3 and 5, the coating layer 50 is not shown.

  The operation of arranging the solder balls 2 using the mask 1 is performed in the following procedure. This arrangement work is performed by a dedicated arrangement apparatus (see FIGS. 1 and 5 of Patent Document 1). First, a flux 17 (see FIG. 2) is printed on the electrode 6 of the work 3. Next, after aligning the mask 1 on the work 3 so that the through hole 12 and the electrode 6 coincide with each other, the mask 1 is fixed. Such an alignment operation is actually performed by aligning the outer peripheral edges of the frame 11 and the workpiece 3. When the alignment operation is completed, the mask body 10 is in contact with the workpiece 3 as shown in FIGS. 2, 4, and 6 by the lower end surface of the projection 15 abutting against the surface of the workpiece 3 in the fixed state. The posture is maintained in a separated posture with a facing gap secured. At this time, a magnet can be arranged below the workpiece 3 and the mask 1 can be attracted to the workpiece 3 side 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 put into the through holes 12 one by one. Thus, the solder ball 2 is adhered and held on the electrode 6 in a temporarily fixed shape by the flux 17. In the charging operation of the solder ball 2 using such a squeegee brush, even if the squeegee brush pressure is applied to the mask 1, the mask 1 can be prevented from being bent by the projections 15, and the charging operation can be performed smoothly and efficiently. Can do.

  As described above, according to the mask 1 according to the present embodiment, the protrusion 15 that forms the facing gap between the mask main body 10 and the workpiece 3 is provided. Therefore, it is possible to efficiently carry out the operation of putting the solder ball 2 into the through hole 12 without leakage.

  A reinforcing frame 11 can be provided on the outer peripheral edge of the mask main body 10, and if the mask main body 10 is formed with a tension applied to the mask main body 10 in such a direction that it contracts inwardly, The expansion of the mask main body 10 accompanying the change in temperature can be absorbed by the tension in the contraction direction. Thereby, it is possible to prevent the positional deviation of the mask main body 10 with respect to the workpiece 3. In addition, since uniform tension can be applied to the entire mask body 10, the solder balls 2 can be mounted on the workpiece 3 with high positional accuracy.

  Next, a method of manufacturing the array mask 1 having such a configuration is shown in FIGS. First, for example, a photoresist layer 31 is formed on the surface of a matrix 30 made of stainless steel or brass having conductivity. The photoresist layer 31 was formed by laminating one or several negative photosensitive dry photoresists to a predetermined height and then thermocompression bonding. Next, as shown in FIG. 7A, a pattern film (glass mask) 32 having a light transmitting hole 32 a corresponding to the protrusion 15 is brought into close contact with the photoresist layer 31, and then an ultraviolet lamp 33 is used for ultraviolet rays. As shown in FIG. 7B, exposure is performed by irradiating light, development and drying are performed, and unexposed portions are dissolved and removed, thereby corresponding to the tapered protrusions 15. A primary pattern resist 34 having a resist body 34 a was formed on the mother die 30. At this time, it is preferable to taper the resist body 34a by using a photoresist that hardly transmits ultraviolet rays or by reducing the exposure amount. Subsequently, the mother die 30 is placed in an electroforming tank bathed under a predetermined condition, and as shown in FIG. 7C, the resist member 34a of the mother die 30 is within the range of the height of the previous resist member 34a. A primary electroformed layer 35 was formed by electroforming an electrodeposited metal such as nickel or copper on the surface not covered with. Here, the primary electroformed layer 35 was formed over substantially the entire surface of the mother die 30 (first electroforming process). 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 electroformed layer 35 and the mother die 30, and then the through hole 12 is formed on the surface of the photoresist layer 36. After closely attaching a pattern film (glass mask) 37 having a corresponding light transmitting hole 37a, exposure is performed by irradiating with ultraviolet light with an ultraviolet lamp 33, and development and drying are performed, and an unexposed portion is exposed. By removing by dissolution, a secondary pattern resist 38 having a resist body 38a corresponding to the mask body 10 was formed on the surface of the primary electroformed layer 35, as shown in FIG. Subsequently, it is placed in an electroforming tank bathed under a predetermined condition, and is covered with the matrix 30 and the resist body 38a within the height range of the previous resist body 38a as shown in FIG. 8 (c). A secondary electroformed layer 39 was formed by electroforming an electrodeposited metal such as nickel or copper on the surface of the primary electroformed layer 35 that was not present (second electroforming step). Next, the secondary pattern resist 38 is dissolved and removed, and the secondary electroformed layer 39 is peeled off from the mother die 30 and the primary electroformed layer 35. Finally, the coating layer 50 is formed on the surface of the secondary electroformed layer 39 corresponding to the lower surface of the mask main body 10 and the surface facing the secondary pattern resist 38 of the secondary electroformed layer 39 corresponding to the inner surface of the through hole 12. By forming, a mask 1 as shown in FIG. 8E and FIG. 2 was obtained.

  If the frame body 11 is attached to the mask 1 thus obtained, an array 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 where a tension is applied to the mask 1 so that stress in the direction of inward contraction acts on the mask 1 itself. The stress is applied by, for example, using the difference in thermal expansion coefficient between the frame 11 and the mask 1 to perform the mounting work of the frame 11 on the outer peripheral edge of the mask 1 in a high temperature environment. This can be realized by contracting the inward side.

  According to the manufacturing method of the mask 1 as described above, since the alignment mask can be manufactured with high accuracy using the electroforming method, the solder balls 2 can be mounted on the work 3 with high positional accuracy. In addition, if the mask body 10 and the protrusion 15 are formed integrally with each other by a single electroforming (second electroforming process) of the mask 1 having the protrusion 15, the mask body 10 and the protrusion Compared to the case where the protrusion 15 is formed separately, there is less possibility of inconvenience such as breakage of the protrusion 15 and the mask 1 having excellent reliability can be obtained with high accuracy. Further, if the protrusion 15 is formed in a tapered shape so as to increase as it approaches the lower surface of the mask main body 10, it is possible to avoid stress concentration on the root of the protrusion 15. Since the protrusion 15 can be brought into contact with the electrodes 6 in a state of being separated from the electrode 6 to which the flux 17 is applied while being able to reinforce firmly, solder caused by adhesion of the flux 17 applied to the electrode 6 to the mask body 10 Mounting failure 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 protrusion 15 to the dimension of the root 15 ″ to 1: 3 or more and the aspect ratio of the protrusion 15 to 3 or more. The protrusion 15 having the desired dimensions 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 shapes of the through holes 12 and the protrusions 15 may be straight or tapered. Here, the case where the through holes 12 and the protrusions 15 are tapered will be described in detail. In the through holes 12, the tapered shape of the mask body 10 toward the surface facing the workpiece 3 is tapered. By providing, it becomes easy to attract the solder ball 2 into the through-hole 12, and by providing a tapered taper toward the surface of the mask body 10 facing the work 3, the mask body 10 faces the work 3. It is possible to prevent the flux from adhering to the periphery of the through hole 12 on the surface side. In addition, in the protrusion 15, the mask can be placed on the work 3 firmly by providing a tapered taper toward the surface of the mask body 10 facing the work 3. By providing a taper that expands toward the surface facing the workpiece 3 of the mask body 10, the strength of the protrusion 15 is ensured even when the electrodes 6 of the workpiece 3 are arranged at a narrow pitch. However, the contact of the projection 15 on the workpiece 3 can be dealt with firmly. Such a shape can be easily obtained by changing the photosensitivity and exposure conditions of the photoresist layers 31 and 36.

(Second Embodiment)
Next, an 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 arrangement 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 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, It can flow on the workpiece through the surface of the protrusion 15. Further, it is possible to more reliably prevent the flux 17 from entering the through hole 12.

  Further, by forming the coating layer 50 so as to cover the entire 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, the bonding strength between them is increased. It is weak (this is because the through hole spacing and the pattern area spacing are narrowed as the bumps are miniaturized, and the external dimensions of the projections 15 arranged between the through holes and between the pattern areas (outside of the pattern area) are also small. This is due to the fact that the joint area between the protrusion 15 and the mask body 10 is reduced), and 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 protrusion 15, which can contribute to prevention of the drop, deformation, and breakage of the protrusion 15. In order to specialize in preventing the protrusion 15 from dropping, deforming, or damaging, a metal layer (Ni, Cu, etc.) is formed on the lower surface of the mask body 10 and the surface of the protrusion 15 by sputtering or electroless plating. Thus, the coating layer 50 is preferably provided.

  10 and 11 show a method of manufacturing the array mask according to 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 mother die 40, and exposure, development, and drying are performed by well-known methods to dissolve and remove unexposed portions, as shown in FIG. A primary pattern resist 41 having a resist body 41 a was formed on the mother die 40. The photoresist layer was formed by laminating one or several negative photosensitive dry film resists to a predetermined height. Next, the mother die 40 is put in an electroforming tank bathed under a predetermined condition, and is covered with the resist body 41a of the mother die 40 as much as the height of the previous resist body 41a as shown in FIG. 10 (c). A primary electrodeposition layer 42 was formed by electroforming an electrodeposited metal on an unfinished surface. In the present embodiment, the primary electrodeposition layer 42 is formed by Ni-Co electroforming. In addition, after forming the primary electrodeposition layer 42, it is preferable that the surface of the primary electrodeposition layer 42 is subjected to mechanical polishing and / or electrolytic polishing such as belt polishing. 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 42. The solder resist layer 43 is 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 portions, whereby a secondary pattern resist 44 having a resist body 44a is formed on the primary electrodeposition layer 42 as shown in FIG. Formed integrally. It is preferable that after the secondary pattern resist 44 is formed, a dropping prevention process such as baking is performed. Thereby, the adhesion between the secondary pattern resist 44 having the resist body 44a and the primary electrodeposition layer 42 can be made stronger. Next, as shown in FIG. 11C, the primary electrodeposition layer 42 and the secondary pattern resist 44 formed on the surface thereof are peeled off from the mother die 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, whereby the arrangement mask shown in FIG. 11 (d) and FIG. 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 from the matrix 40. 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 material of the coating layer 70 is as follows. The protrusion 15 is made of a material different from the material.

  As described above, this mask is used to mount solder balls on the workpiece electrodes, but during the solder ball arrangement process (transfer mounting), dirt or the like may adhere to the mask. In order to remove this, the mask is washed as necessary. When cleaning the mask using a solvent, there is a possibility that this solvent may cause adverse effects such as stickiness on the surface of the material constituting the projection, but because the coating layer is on the surface of the projection, Protects against such adverse effects.

  Therefore, in the mask of this embodiment, the coating layer 70 is formed on the surface of the protrusion 15 in order to prevent adverse effects on the protrusion 15 formed of resin, and the coating layer 70 constitutes the protrusion 15. It is made of a material different from (resin). The coating layer 70 can be formed of, for example, a photosensitive material mainly composed of an acrylic resin in addition to the above materials.

  The method for manufacturing the array mask is the same as that described above (see FIG. 10) from the preparation of the mother mold to the formation of the primary electrodeposition layer and the removal of the resist body. Next, by forming a solder resist layer on the surface of the primary electrodeposition layer 42 and performing exposure, development, and drying, a secondary pattern resist having a resist body 60a as shown in FIG. 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 developing type photosensitive material, and 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 is peeled off from the mother die 40 together with the secondary pattern resist 60 and the coating layer 70 formed on the surface thereof, whereby the arrangement mask 1 shown in FIGS. 14C and 13 is obtained. Can be obtained. 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. Alternatively, 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 mother 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, it is preferable that after the secondary pattern resist 60 and the coating layer 70 are formed, a dropping prevention process such as baking is performed. Thereby, the adhesion between the primary electrodeposition layer 42 and the secondary pattern resist 60 and between the secondary pattern resist 60 and the coating layer 70 can be made stronger. Such drop-off prevention treatment may be performed every time the secondary pattern resist 60 and the coating layer 70 are formed, or may be performed after the coating layer 70 is formed on the surface of the secondary pattern resist 60.

  The mask 1 obtained by such a manufacturing method is resistant to cleaning (solvent), and it is possible to prevent sticking from occurring on the protrusion 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, the projection 15 can be prevented from being damaged or missing.

  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 body 10 (the protrusion 15 Before the coating layer 70 is formed on the surface of the protrusion 15, the protrusion 15 is washed to generate stickiness on the surface of the protrusion 15, and the coating layer 70 is formed on the surface, whereby the protrusion 15 and the coating layer are formed. The adhesion with 70 can be made stronger.

  Further, as shown in FIG. 13C, the protrusion 15 can be formed only with the material forming the coating layer 70. The material for forming the coating layer 70 is a material to which the flux is difficult to adhere, and specifically includes a resin mixture in which barium sulfate and / or silicon dioxide is contained in an acrylic resin. This resin mixture is excellent in solvent resistance. More specifically, the resin mixture has a width dimension of 0.2 to 3.0 mm (0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1.0 mm, 2.0 mm, 3.0 mm). Each of the masks provided with the protrusions of a total of 7 products) on the mask body made of a nickel-cobalt alloy is applied to a cleaning agent (manufactured by Kaken Tech Co., Ltd.) for 6 to 24 hours (6 hours, 12 hours, 24 hours). 3 times) It was confirmed that no protrusions were peeled off in all the masks. Furthermore, since the resin mixture has good compatibility with the mask body 10 and good adhesion, it is possible to narrow the width dimension of the protrusion 15. Since the resin mixture has hardness (5H-6H in the JIS standard scratch hardness test), if the mask body thickness is 100 μm or less and the width of the protrusion is larger than 5 mm, the mask warps. Therefore, the width of the protrusion is preferably 5 mm or less. Thus, the coating layer 70 is formed mainly of a material such as a fluororesin, a silicon resin, an acrylic resin, or the like. And it is possible to comprise the projection part 15 by using such a material as a main component.

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

  In each of the above embodiments, the protrusions 15 (supports 15b) and the through holes 12 may be arranged so that the protrusions 15 (supports 15b) surround one through hole 12, or one protrusion 15 May be disposed so as to be surrounded by the through hole 12. When the projecting portion 15 is disposed so as to surround one through-hole 12, the shape of the projecting portion 15 is not limited to a portion provided like a support column, but may be provided in an endless frame shape. Further, the shape of the protrusion 15 is not limited to the crosspiece 15a or the column, but may be a polygon such as a rhombus or a hexagon or an ellipse. Furthermore, in these shapes, as shown in FIG. 10, an elongated shape and / or rounded corners are preferable. In this way, by adjusting the longitudinal direction and the major axis direction of these shapes to a certain direction, for example, when the back surface of the mask 1 is cleaned, the cleaning unit (cloth, sponge, etc.) is caught by the protrusion 15. In addition, it is possible to eliminate as much as possible the risk of breakage of the projections 15 and smooth cleaning. 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 only on the lower end surface (tip surface) of the protruding portion 15, and the surface of the root portion 15 b of the protruding portion 15 does not necessarily have an elongated shape in terms of strength and the like.

  Moreover, in each said embodiment, you may vary the thickness of the coating layers 50 and 70 by the inner surface of the through-hole 12, and the surface of the mask main body 10 and the projection part 15. FIG. 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. As a result, it is possible to more reliably prevent the flux from adhering 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 material that is slippery (small 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. As the thickness of the solder ball 2 increases, the area becomes larger. Therefore, when the solder ball 2 is made with a squeegee brush, the squeegee brush and the solder ball 2 can be moved smoothly, and improvement in productivity and work efficiency can be expected. If T1 <T2, when the protrusions 15 are separately formed on the lower surface of the mask body 10, the protrusions 15 can be more reliably prevented from dropping, deforming, or breaking. In addition, as a formation method of this coating layer 50, there exist various methods, such as a dipping method and a spray method, but when forming the coating layer 50, it is good to cover parts other than the desired formation part with a protective sheet. Further, when it is desired to form the coating layer 50 thickly, the portion to be thickened is sprayed locally, or the direction in which the mask 1 is immersed is changed (for example, when the mask body 10 lower surface is desired to be thicker, the lower surface of the mask body 10 is formed). And the immersion surface may be immersed in a parallel state, and if it is desired to increase the thickness of the inner surface of the through-hole 12, it may be realized by immersing 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 piece 6 Electrode 10 Mask main body 12 Through-hole 15 Protrusion part 15a Crosspiece 15b Post 15c Post 15 'Tip part 15 "Root part 30, 40 Master mold 31, 36, 43 Photoresist layer (solder resist layer)
34, 41 Primary pattern resist 34a, 41a Resist body 35, 42 Primary electrodeposition layer 38, 44, 60 Secondary pattern resist 38a, 44a Resist body 39 Secondary electrodeposition layer 50, 70 Coating layer

The present invention is an array mask in which the solder balls 2 are mounted at predetermined positions on the work 3 by swinging the solder balls 2 into the through holes 12 corresponding to the predetermined array pattern. A mask main body 10 in which a plurality of regions are formed and a protrusion 15 provided on the lower surface of the mask main body 10, and a coating layer is formed at least in a pattern region on the lower surface of the mask main body (10). To do. Further, the protrusion 15 is provided in the vicinity of the pattern area of the mask body 10, and a coating layer is formed on the surface of the protrusion 15. A coating layer is formed on the pattern region on the lower surface of the mask main body 10 and on the surface of the protrusion 15 provided in the vicinity of the pattern region.

The present invention is also a method for manufacturing an array mask in which the solder balls 2 are mounted at predetermined positions on the work 3 by swinging the solder balls 2 into the through holes 12 corresponding to the predetermined array pattern . First, the mask main body 10 having a plurality of pattern regions including the through holes 12 is formed. Next, the protrusion 15 is formed on the mask body 10. Next, a coating layer is formed on the mask body 10. The coating layer is formed at least in the pattern region on the lower surface of the mask body 10. Further, it is preferable that the protrusion 15 is provided in the vicinity of the pattern region on the lower surface of the mask body 10 and the coating layer is formed on the surface of the protrusion 15. The coating layer may be formed on the pattern region on the lower surface of the mask body 10 and the surface of the protrusion 15 provided in the vicinity of the pattern region.

According to the onset bright, the pattern area of the lower surface of at least the mask body, the coating layer is formed, it is possible to prevent the state that flux pattern region of the lower surface of the mask body is attached. In addition, by forming a coating layer on the surface of the protrusion provided in the vicinity of the pattern area of the mask body, the coating layer functions as a protective layer for the protrusion. Can prevent damage.

Claims (6)

An array mask for mounting the solder balls (2) at predetermined positions on the workpiece (3) by swinging the solder balls (2) into the through holes (12) corresponding to the predetermined array pattern,
A mask main body (10) in which a large number of pattern regions including the through holes (12) are formed, and a protrusion (15) provided on the surface of the mask main body (10) facing the workpiece (3). Prepared,
A mask for arrangement, wherein a coating layer is formed at least in a pattern region on the lower surface of the mask body (10).   The said mask main body (10) and the said projection part (15) are formed by the separate body, The mask for arrangement | sequence of Claim 1 characterized by the above-mentioned.   The alignment mask according to claim 1 or 2, wherein the coating layer (50) is formed so as to cover the entire lower surface of the mask main body (10) and the surface of the protrusion (15).   4. The alignment mask according to claim 1, wherein the coating layer (50) is formed with a thickness of 1 [mu] m or less. A mask main body (10) in which a large number of pattern regions including through-holes (12) are formed, and a protrusion (15) provided on the surface facing the workpiece (3) of the mask main body (10), A method for manufacturing an array mask in which a coating layer (50) is formed on at least the lower surface of the mask body (10),
Forming a primary pattern resist (41) having a resist body (41a) on the matrix (40);
Forming a primary electrodeposition layer (42) on the matrix (40) using the resist body (41a);
Forming a secondary pattern resist (44) having a resist body (44a) on the primary electrodeposition layer (42);
And a step of forming the coating layer (50) on the surface of the primary electrodeposition layer (42).   In the step of forming the coating layer (50), the coating layer is formed on the surface of the primary electrodeposition layer (42) having the secondary pattern resist (44) and on the surface of the secondary pattern resist (44). (50) is formed, The manufacturing method of the mask for arrangement | sequence of Claim 5 characterized by the above-mentioned.