JP5156118B2 - Mask for array - Google Patents

Description

The present invention is used, for example, to form the solder bumps, about the sequence for mask.

  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 board, and a rigid board, an arrangement process in which solder balls are arranged and mounted on the flux, and the solder balls are heated and melted. The bump is formed through the heating 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, solder balls are arranged using an alignment mask (hereinafter, simply referred to as “mask” as appropriate) having positioning through holes into which solder balls can be inserted corresponding to the arrangement pattern of the electrodes of the electronic component. It is mounted on the workpiece. Specifically, after aligning the mask with respect to the workpiece so that the through-holes and the electrodes coincide with each other, the solder balls placed on the mask are swept with a squeegee, a brush, etc. Solder balls one by one. Then, by adsorbing 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, with the miniaturization of electronic devices, the pad interval in the chip package has been narrowed. In order to meet such a demand, a mask with a reduced width of the protrusion is desired. However, if the width of the protrusion is simply reduced, the strength of the base of the protrusion is insufficient. It becomes easy to break due to stress concentration.
An object of the present invention is to provide an arrangement for mask which can satisfy the above requirements.

The present invention is an array mask that has through holes 12 corresponding to a predetermined array pattern and mounts the solder balls 2 at predetermined positions on the work 3 by swinging the solder balls 2 into the through holes 12. The protrusion 15 is provided on the lower surface of the mask body 10, and the base 15 b width of the protrusion 15 increases toward the lower surface of the mask body 10, and the base 15 b of the protrusion 15 is provided with a radius. It is characterized by. Further, the lower end surface of the protrusion 15 is an oval shape, an oval shape, and a polygonal shape with rounded corners. In addition, the longitudinal direction and the major axis direction of an elliptical shape, an elliptical shape, and a polygonal shape with rounded corners are aligned in a certain direction. The protrusion 15 is characterized in that the tip has a straight shape and the root is tapered toward the tip. In addition, a radius is provided at the tip 15 a of the protrusion 15. Further, the ratio between the width of the tip of the protrusion 15 and the width of the root is 1 to 3 or more.

According to the present invention, the protrusion 15 is provided on the lower surface of the mask body 10, the width of the base 15 b of the protrusion 15 increases toward the lower surface of the mask body 10, and the base 15 b of the protrusion 15 is provided with a radius. Therefore, the strength of the base of the protrusion 15 is improved, the tip of the protrusion 15 can be firmly abutted between the electrodes 6, and the flux 17 applied to the electrode 6 can be applied to the mask body 10 and the protrusions. Thus, the solder ball 2 can be placed at a desired position by avoiding the adhesion to the solder .

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 which shows typically 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 top view which shows 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 which shows typically 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 explanatory drawing of another 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 mask for arrangement | sequence which concerns on another embodiment of this invention. It is a figure which shows the lower end surface shape of the projection part in the mask for arrangement | sequence which concerns on 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 installed. 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.

  A reinforcing frame 11 can be attached to the mask body 10. This frame 11 is a flat plate made of a material such as aluminum, 42 alloy, Invar material, SUS430, and the like, and has one rectangular opening corresponding to the mask body 10 at the center of the board surface. Then, one mask body 10 is held by one frame body 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. Further, the thickness of the mask main body 10 is preferably set to 200 μm in this embodiment as a range of 10 μm or more.

  As shown in FIG. 2, a protrusion 15 is provided on the lower surface side of the mask body 10 (mask 1), that is, the surface facing the workpiece 3, so as to ensure a facing gap with the workpiece 3. ing. The projecting portion 15 abuts against the upper surface of the work 3 at the time of arraying work to ensure a facing gap between the mask main body 10 and the work 3. As shown in FIGS. 2 and 3, each protrusion 15 is formed between the through holes 12 and tapered from the lower surface of the mask body 10. In this embodiment, the protrusion 15 has a truncated cone shape. ing. The base of the projection 15 is preferably located in the vicinity of the through hole 12 on the lower surface of the mask body 10, and in this embodiment, is located at the intersection of the inner surface of the through hole 12 and the lower surface of the mask body 10. . In the present mask 1, it is preferable that the ratio between the height of the protrusion 15 and the thickness of the mask body 10 is 2 to 1 or more. It is preferable to satisfy this when the thickness of the mask body 10 is in the range of 10 to 300 μm. Moreover, it is preferable that the ratio between the diameter L1 of the tip of the protrusion 15 and the diameter L2 of the root is 1: 3 or more. Furthermore, it is preferable that the ratio of the diameter of the tip of the protrusion 15, the diameter of the base, and the width between the through holes 12 is 1 to 3 to 3 or more. The protrusion 15 preferably has a large aspect ratio (ratio between the height of the protrusion 15 and the tip diameter). In this embodiment, the aspect ratio is 3. Here, in FIG. 3, a convex part having the same height as the protrusion 15 is provided between the adjacent pattern regions so as to come into contact when the mask 1 is placed on the work 3, but in FIG. As shown, it may be a form in which adjacent pattern regions are recessed (a form in which no convex part is provided). According to this, it is possible to place the mask 1 on the workpiece 3 with good followability. In FIGS. 3 and 4, what is indicated by reference numeral 15 is the lower end surface of the protruding portion 15, and the root of the protruding portion 15 is not shown.

  Here, the perspective view of FIG. 1, the longitudinal sectional view of FIG. 2, and the plan views of FIGS. 3 and 4 do not show the actual state of the mask 1, but schematically show it. Further, the opening dimension of the through-hole 12 and the thickness dimension of the mask main body 10 and the like in FIG. 1 and the like are shown in such dimensions for the convenience of drawing.

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, a mask is disposed below the workpiece 3, and the mask body 10 is shown in FIG. The posture is maintained in a separated posture in which a gap facing the workpiece 3 is secured. Even when the surface of the workpiece 3 is slightly wavy, the mask main body 10 is inseparably integrated so that the lower end surface of the projection 15 is brought into contact with the surface of the workpiece 3 to match the waviness of the surface of the workpiece 3. Can be fixed.

  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. As a result, the solder ball 2 is adhered and held to the flux 17 in a temporarily fixed shape. 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. This makes it 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 body 10, and if the mask body 10 is formed in a state in which tension is applied to the mask body 10 in a direction in which it shrinks inward, The expansion of the mask main body 10 due to the change in the ambient 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.

  5 and 6 show a method of manufacturing the array mask 1 according to this embodiment. First, as shown in FIG. 5A, a photoresist layer 31 is formed on the surface of a mother mold 30 made of, for example, 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, after the pattern film 32 (glass mask) having the light transmitting holes 32a corresponding to the protrusions 15 is brought into close contact with the photoresist layer 31, exposure is performed by irradiating ultraviolet light with the ultraviolet lamp 33, A primary pattern resist 34 having a resist body 34a corresponding to the tapered protrusion 15 as shown in FIG. 5B is obtained by dissolving and removing unexposed portions by performing development and drying processes. Was formed on the matrix 30. At this time, it is preferable that the resist body 34a has a taper by using a photoresist that does not easily transmit ultraviolet rays or by reducing the exposure amount.

  Subsequently, the mother die 30 is put in an electroforming tank bathed under a predetermined condition, and as shown in FIG. 5C, 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. 5D, 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. 6A, 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 contacting the pattern film 37 having the corresponding light transmitting hole 37a, exposure is performed by irradiating ultraviolet light with the ultraviolet lamp 33, and development and drying are performed to dissolve and remove unexposed portions. Thus, as shown in FIG. 6B, a secondary pattern resist 38 having a resist body 38 a corresponding to the mask body 10 was formed on the surface of the primary electroformed layer 35.

  Subsequently, it is placed in an electroforming tank bathed under a predetermined condition, and as shown in FIG. 6C, it is covered with the matrix 30 and the resist body 38a within the range of the height of the previous resist body 38a. 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 then the secondary electroformed layer 39 is peeled off from the mother die 30 and the primary electroformed layer 35, whereby a mask as shown in FIG. 6 (d) and FIG. 1 was obtained. If the frame 11 is attached to the mask 1, an array mask 1 as shown in FIG. 1 is obtained.

  The secondary electroformed layer 39, that is, the mask 1, can be held on the frame body 11 in a state where a tension is applied so that a stress in the direction of shrinking inward acts on the secondary electroformed layer 39. 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, the arraying mask can be manufactured with high accuracy by the electroforming method, so that the solder balls 2 can be mounted on the workpiece 3 with high positional accuracy. If the mask 1 having the protrusions 15 can be formed in one piece by a single electroforming operation (second electroforming process), the protrusions 15 can be formed as compared with the case where the protrusions 15 are retrofitted. There is little possibility that inconvenience such as breakage occurs, and the mask 1 having excellent reliability can be obtained with high accuracy. Further, if the protrusion 15 is formed 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 (base) of the protrusion 15, so that the strength of the protrusion 15 is firmly secured. The protrusions 15 can be brought into contact with the electrodes 6 while being separated from the electrodes 6 to which the flux 17 is applied, so that the solder balls formed by the adhesion of the flux 17 applied to the electrodes 6 to the mask body 10 can be achieved. 2 mounting failure can be prevented. This becomes more effective by setting the ratio of the diameter of the tip of the protrusion 15 to the diameter of the root to be 1: 3 or more and setting the aspect ratio of the protrusion 15 to be 3 or more.

  Further, the protrusion 15 having a desired aspect ratio can be easily obtained by adjusting the resist pattern. In addition, in this embodiment, although the through-hole 12 and the projection part 15 are made straight, it is good also as a taper shape. Such a shape can be 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. 7, the protrusion 15 has a divergent shape whose diameter increases as it approaches the lower surface of the mask, and the side surface of the protrusion 15 has an arc shape. Since the other points are basically the same as those of the first embodiment, the same members as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  8 and 9 show a method for manufacturing a solder ball arrangement mask according to the second embodiment of the present invention. First, as shown in FIG. 8A, a photoresist layer 31 is formed on the surface of a mother mold 30 made of, for example, 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, after a pattern film 32 (glass mask) having a light transmitting hole 32a corresponding to the through hole 12 is adhered on the photoresist layer 31, exposure is performed by irradiating ultraviolet light with an ultraviolet light lamp 33, The primary pattern resist 34 having the resist bodies 34a corresponding to the through holes 12 is formed on the matrix 30 as shown in FIG. 8B by performing development and drying processes to dissolve and remove unexposed portions. Formed.

  Subsequently, the mother die 30 is put in an electroforming tank bathed under a predetermined condition, and nickel or the like is formed on the surface not covered with the resist member 34a of the mother die 30 within the range of the height of the previous resist member 34a. Then, a primary electroformed layer 35 corresponding to the mask 1 is formed on the entire surface of the mother die 30, and the surface of the primary electroformed layer 35 is polished. After that, as shown in FIG. 8C, the resist body 34a was dissolved and removed. The steps so far are substantially the same as those in the first embodiment.

  Next, as shown in FIG. 8D, a conductive layer 40 such as nickel or copper is formed on the surface of the mother die 30 and the primary electroformed layer 35 by plating. At this time, the conductive layer 40 on the corner of the primary electrodeposition layer 35 is formed in an arc shape. Thus, a pattern corresponding to a protrusion having an arcuate side surface is obtained. The curvature of the arc-shaped portion can be obtained by adjusting the thickness of the conductive layer 40. Further, the step of forming the conductive layer 40 may be performed after forming a secondary resist pattern 38 to be described later on the primary electroformed layer 35. Here, since the conductive layer 40 functions as a peeling layer by forming the conductive layer 40, it is compared with the case where the secondary electroformed layer 35 is directly formed on the mother die 30 as in the first embodiment. In addition, the secondary electroformed layer 35 can be easily peeled from the mother die 30. The mask 1 may be formed by integrally laminating the secondary electroformed layer 35 and the conductive layer 40, but it is preferable to remove the conductive layer 40, so that the secondary electroformed layer 35 can be more easily separated. Therefore, by performing an adhesion treatment such as strike plating on the mother die 30, the conductive layer 40 is fixed to the mother die 30, so that the secondary electroformed layer 35 can be more easily separated.

  Next, as shown in FIG. 9A, a photoresist layer 36 is formed on the surface of the conductive layer 40, and a light transmitting hole corresponding to the through hole 12 is formed on the surface of the photoresist layer 36. After the pattern film 37 having 37a is adhered, exposure is performed by irradiating ultraviolet light with an ultraviolet lamp 33, development and drying are performed, and unexposed portions are dissolved and removed. As shown in b), a secondary pattern resist 38 having a resist body 38 a was formed on the surface of the conductive layer 40. Next, it is put into an electroforming tank bathed under a predetermined condition, and as shown in FIG. 9C, the conductive layer 40 not covered with the resist body 38a is within the height range of the previous resist body 38a. Electrodeposited metal such as nickel or copper was electroformed on the surface to form a secondary electroformed layer 39 (second electroforming process). Finally, the secondary pattern resist 38 is removed, and the secondary electroformed layer 39 is peeled off from the mother die 30, the primary electroformed layer 35, and the conductive layer 40, as shown in FIG. 9D and FIG. Such a mask 1 is obtained.

  As described above, the mask of this embodiment forms the conductive layer 40 on the master mold 30 and the primary electroformed layer 35, thereby forming the intersection 15 between the inner surface 12a of the through hole and the lower surface 10a of the mask main body as a root 15b and going to the tip. Accordingly, it is possible to easily form the projecting portion 15 that has a tapered shape that is gradually narrowed as the side surface is arcuate. Thereby, the damage which arises when stress concentrates especially on the root of the projection part 15 can be prevented. In addition to this, even when the flux 17 adheres to the projection 15 when the mask 1 is placed on the workpiece 3, the side surface of the projection 15 has an arc, so that the through-hole 12 of the flux 17 is provided. Since the flux 17 adheres to the through hole 12, it is possible to eliminate the possibility of causing a mounting failure of the solder ball 2. The position of the base 15b of the protrusion 15 is not limited to the position at the intersection of the mask main body lower surface 10a and the through hole inner surface 12a as shown in FIG. As shown in FIG. 7, the through-holes 12 on the mask main body lower surface 10 a as shown in FIG. 7C, even at positions that are sufficiently spaced (separated) from the through-holes 12 on the mask main body lower surface 10 a. It may be a position where a minute gap is taken. 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 is at any position on the side of the projection 15. There may be no portion approaching the electrode 6 to which 17 is attached, that is, a state where a certain distance is maintained from the electrode 6 to which the flux 17 is attached. Moreover, as shown in the enlarged view of the protrusion 15 in FIG. 7A, a desired radius may be provided not only on the side surface and the base 15b of the protrusion 15 but also on the tip 15a. This can be realized by adjusting the thickness of the conductive layer 40, whereby the contact area of the protrusion 15 to the work 3 can be further reduced, and the possibility that the flux 17 adheres to the protrusion 15 is possible. Decrease. Thus, the above-mentioned effect can be obtained by providing a radius at the tip 15a and / or the root 15b of the protrusion 15. Here, of course, the base 15b of the protrusion 15 includes, as a matter of course, an arc having a small curvature as close as possible to a straight line. The protrusion 15 may have a shape combining a straight shape and a tapered shape.

  In the above-described embodiment, the mask 1 is integrally formed with the protrusion 15, but the protrusion 15 may be integrally formed with another member. In the mask, for example, if the protrusion 15 is formed of a nonmagnetic material such as copper or aluminum, the mask 1 is fixed to the mask 1 when the mask 1 is fixed to the work 3 by the magnetic attractive force of the magnet as described above. On the other hand, since the magnetic force acts uniformly, the mask 1 is not inadvertently bent, and the positional accuracy of the through hole 12 with respect to the electrode 6 can be improved. Such a mask 1 is nonmagnetic in the second electroforming process (see FIGS. 6C and 9C) until the height of the primary electroformed layer 35 corresponding to the pattern of the protrusions 15 is equal. The body metal can be formed by plating or the like, and the others can be manufactured by forming a magnetic metal such as iron, nickel, nickel-cobalt or the like by electroforming or the like.

  Further, in the case where the protrusion 15 is formed of a non-magnetic material, it is not limited to metal but may be formed of resin. The manufacturing method of the mask 1 is the same as that shown in FIGS. 8A to 8D in FIGS. 8 and 9, and then a photoresist layer is formed on the surface of the conductive layer 40. In addition, after a pattern film having a light transmitting hole corresponding to the protrusion 15 is brought into close contact with the surface of the photoresist layer, exposure is performed by irradiating ultraviolet light with an ultraviolet lamp, and development and drying are performed. As shown in FIG. 10 (a), each process is performed to dissolve and remove the unexposed portions, or by embedding and curing a liquid resin in the portions corresponding to the protrusions 15. A secondary pattern resist 41 having 41 a was formed on the surface of the conductive layer 40. Subsequently, after forming a photoresist layer on the surface of the conductive layer 40 and the secondary pattern resist 41, a pattern film having a light transmitting hole corresponding to the through hole 12 is adhered to the surface of the photoresist layer. Then, exposure is performed by irradiating with ultraviolet light with an ultraviolet lamp, development and drying are performed, and unexposed portions are dissolved and removed, so that a resist body is obtained as shown in FIG. A tertiary pattern resist 42 having 42 a was formed on the surface of the conductive layer 40. Note that the secondary pattern resist 41 may be formed after the tertiary pattern resist 42 is formed first, or the secondary pattern resist 41 and the tertiary pattern resist 42 may be formed simultaneously.

  Thereafter, the surface of the conductive layer 40 and the secondary pattern resist 41 that are preferably not covered with the tertiary pattern resist 42 is subjected to an adhesion treatment, and at least the surface of the secondary pattern resist 41 is provided with a conductive layer by vapor deposition or sputtering. Then, it is put into an electroforming tank bathed under a predetermined condition, and as shown in FIG. 10C, the conductive layer not covered with the resist body 42a within the height range of the previous resist body 42a. Electrodeposition metal such as nickel or copper was electroformed on the surface of 40 and the resist body 41a to form a secondary electroformed layer 43 (second electroforming step). Finally, the tertiary pattern resist 42 is removed, and the secondary electroformed layer 43 is peeled off from the mother die 30, the primary electroformed layer 35, and the conductive layer 40, whereby the mask 1 as shown in FIG. Can be obtained. Of course, the mask 1 can also be formed only by vapor deposition or sputtering.

  Thus, if the projection 15 is formed of a resin that is a non-magnetic material, a cushioning action derived from the elasticity of the resin is exhibited, and the workpiece 3 is damaged when the projection 15 contacts the workpiece 3. The risk of doing so is reduced. In order to achieve this effect remarkably, in the mask 1, it is preferable to form not only the protrusions 15 but also all of the portions that come into contact with the work 3 with resin. As a result, the magnetic force acts uniformly on the mask 1, so that the mask 1 is not inadvertently bent and the positional accuracy of the through-hole 12 with respect to the electrode 6 can be improved.

  When the frame 11 is provided on the mask 1 obtained by the above manufacturing method, the frame 11 can be formed by utilizing the adhesiveness of a solder resist that is an adhesive resist. Therefore, the mask production process can be reduced as compared with the case where the frame body 11 is separately attached with an adhesive or the like, which can contribute to the reduction of the manufacturing cost of the mask. Further, in this manufacturing method, since the solder resist is altered to form the protrusions 15, it is excellent in that a mask having the nonmagnetic protrusions 15 can be formed with high production efficiency.

  The protrusion 15 in the present invention can be provided with a desired shape by the primary resist pattern 34 and an arbitrary radius by the conductive layer 40. In addition, in the said embodiment, although arrangement | positioning of the projection part 15 and the through-hole 12 becomes a form as shown to Fig.11 (a), it is not restricted to this, The position corresponding to the electrode 6 at the through-hole 12 11 (b) to FIG. 11 (d), the projection 15 is surrounded by the through-hole 12 so that the projection 15 surrounds the single through-hole 12. Alternatively, FIG. 11 shows the positional relationship between the through-hole 12 and the tip end surface of the protruding portion 15, and the base 15b of the protruding portion 15 is not shown. The shape of the lower end surface of the protrusion 15 is not limited to a circle, but may be a polygon such as a rhombus or a hexagon, or an ellipse. Furthermore, in these shapes, those having an elongated shape and / or rounded corners are preferable (see FIGS. 12A to 12H). 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. Note that the elongated shape is only on the lower end (tip) surface of the protrusion 15, and the surface of the base 15 b of the protrusion 15 does not necessarily have an elongated shape in terms of strength and the like.

DESCRIPTION OF SYMBOLS 1 Mask 2 Solder ball 3 Work piece 6 Electrode 10 Mask main body 12 Through-hole 15 Protrusion part 15a Tip part 15b Base part 30 Master mold 31 Photoresist layer 34 Primary pattern resist 34a Resist body 35 Primary electroformed layer 36 Photoresist layer 38 Secondary Pattern resist 38a Resist body 39 Secondary electroformed layer 40 Conductive layer 41 Secondary pattern resist 41a Resist body 42 Tertiary pattern resist 42a Resist body 43 Secondary electroformed layer

Claims (6)

A through hole (12) corresponding to a predetermined arrangement pattern is provided, and the solder ball (2) is mounted in a predetermined position on the work (3) by swinging the solder ball (2) into the through hole (12). A mask for the array,
A protrusion (15) is provided on the lower surface of the mask body (10), and the base (15b) width of the protrusion (15) increases toward the lower surface of the mask body (10 ). An array mask , wherein a radius is provided at the base (15b) . 2. The array mask according to claim 1, wherein a lower end surface of the projecting portion is an oval shape, an oval shape, and a polygonal shape with rounded corners. 3. The array mask according to claim 2, wherein the longitudinal direction and the major axis direction of an elliptical shape, an elliptical shape, and a polygonal shape with rounded corners are aligned in a certain direction. The array of any one of claims 1 to 3, wherein the protrusion (15) has a straight tip and a root that is tapered toward the tip. mask. The array mask according to any one of claims 1 to 4, wherein a radius is provided at a tip (15a) of the projection (15). The array mask according to any one of claims 1 to 5, wherein the ratio of the width of the tip of the protrusion (15) to the width of the base is 1 to 3 or more.

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