JP2021184483A - Metal mask - Google Patents

Abstract

To provide a metal mask capable of accurately forming an object at a predetermined position on a workpiece.SOLUTION: In a metal mask provided with a through hole 12 corresponding to a predetermined pattern, the through hole 12 includes an introduction hole portion 15 that opens in a surface of a mask body 10, and a holding hole portion 16 provided on the lower side of the introduction hole portion 15, and height dimensions of the holding hole portion 16 on one side edge and the other side edge thereof are set to heights different from each other and in a cross-sectional view in a thickness direction of the mask body 10, an inner surface of one side edge of the introduction hole portion 15 faces the inner surface of the other side edge of the holding hole portion 16.SELECTED DRAWING: Figure 6

Description

The present invention relates to a metal mask in which through holes corresponding to a predetermined pattern are provided and an object (pillar, ball, paste, etc.) is formed (mounted, arranged, printed, applied) at a predetermined position on a work.

As an example of a metal mask, an array mask for mounting a conductive ball made of solder at a predetermined position on a work is known, for example, in Patent Document 1. The array mask of Patent Document 1 is formed with a plurality of openings for dropping conductive balls. The opening is provided so as to correspond to the formation pattern of the electrode pad of the substrate (work). A slope-shaped ball guiding portion is formed on the upper peripheral edge of the opening, and the ball guiding portion is composed of an inclined surface that gently slopes downward toward the opening. At the time of dropping, a large number of conductive balls are supplied on the mask for arrangement and dispersed by a squeegee brush or the like, so that the conductive balls are guided toward the opening by the ball guiding portion, and the conductive balls are smoothly smoothed. It can be dropped into the opening.

Japanese Unexamined Patent Publication No. 2011-44616

In recent years, in surface mount type packaged electronic elements, the density of electrode formation patterns for connecting to circuit boards has been increasing, and the aspect ratio (higher) is higher than that of conventional conductive balls. Cylindrical conductive pillars that can narrow the pitch of mounting intervals (ratio of aspect ratio) are being adopted. In the arrangement mask of Patent Document 1, the structures of the opening and the ball guiding portion are optimized so that the conductive ball can be smoothly dropped. However, even if the structure of the arrangement mask of Patent Document 1 is applied to the arrangement mask of the columnar conductive pillar, the same effect cannot be obtained. That is, in order for the columnar conductive pillar to fall into the opening (arrangement through hole), one end of the conductive pillar must be oriented toward the opening. Further, the conductive pillar needs to slide down the ball guiding portion with one end facing the opening. However, it is difficult for the conductive pillar to slide down in the ball guiding portion formed by the inclined surface that is gently inclined downward. Further, if the ball guiding portion rolls down while the peripheral surface of the conductive pillar in the lying posture faces the opening, the conductive pillar cannot fall into the opening and the conductive pillar closes the opening, so that the opening is covered. The conductive pillar cannot be dropped.

An object of the present invention is to allow an object such as a conductive pillar to smoothly pass through a through hole so that the object forming work can be completed in a short time and the object can be accurately formed at a predetermined position on the work. To provide a metal mask.

The present invention is intended for an arrangement mask in which a columnar conductive pillar 2 is dropped into an arrangement through hole 12 corresponding to a predetermined arrangement pattern, and the conductive pillar 2 is mounted at a predetermined position on the work 3. The array through holes 12 are provided at the introduction hole portion 15 which is opened on the surface of the mask main body 10 to guide the conductive pillar 2 to be introduced into the inside of the array through hole 12, and the conductive pillar is provided under the introduction hole portion 15. A holding hole portion 16 for positioning 2 is provided, and the lower end of the introduction hole portion 15 and the upper end of the holding hole portion 16 are smoothly continuous. The introduction hole portion 15 is formed in a bell mouth shape that expands toward the surface side of the mask main body 10, and the holding hole portion 16 has an opening diameter D1 of the hole portion 16 larger than the diameter of the conductive pillar 2. It is characterized by being formed of straight holes set slightly larger.

The array through hole 12 can have a configuration in which a relief hole portion 17 having an opening diameter D3 larger than the opening diameter D1 of the hole portion 16 is provided on the lower side of the holding hole portion 16.

When the total height dimension of the introduction hole portion 15 and the holding hole portion 16 is H1 and the height dimension of the escape hole portion 17 is H2, the height dimension H1 of the former is the same as the height dimension H2 of the latter, or it is the same. Set larger than.

When the height dimension of the introduction hole portion 15 is H3 and the height dimension of the holding hole portion 16 is H4, the height dimension H4 of the latter is set to be the same as or larger than the height dimension H3 of the former.

The curvature of the cross-sectional shape of the introduction hole portion 15 is formed so as to change in magnitude in the circumferential direction of the introduction hole portion 15.

The curvature of the cross-sectional shape of the introduction hole portion 15 is formed so as to gradually change from large to small from one side edge toward the other side edge.

The present invention relates to a method for manufacturing an arrangement mask in which a conductive pillar 2 is mounted at a predetermined position on a work 3 by transferring a columnar conductive pillar 2 into an arrangement through hole 12 corresponding to a predetermined arrangement pattern. And. In the method for manufacturing an arrangement mask, a primary patterning step of providing a primary pattern resist 25 having a primary resist body 24 corresponding to an escape hole portion 17 on the surface of a master mold 21 and introduction into the surface of the primary pattern resist 25. A secondary patterning step of providing a secondary pattern resist 29 having a secondary resist body 28 corresponding to the hole portion 15 and the holding hole portion 16, and an electrodeposition metal electrodeposition on the master mold 21 to form an electrocast layer 30. Including the electrocasting process to form. In the electrocasting process, the electrodeposited metal is electrodeposited within a range that overcomes the upper end edge of the primary resist body 24 and does not overcome the upper end edge of the secondary resist body 28 to form the bellmouth-shaped introduction hole portion 15. It is a feature.

In the secondary patterning step, the secondary pattern resist 29 is provided in a state where the central axis Q2 of the secondary resist body 28 is located on the same axis as the central axis Q1 of the primary resist body 24.

In the secondary patterning step, the secondary pattern resist 29 is provided in a state where the central axis Q2 of the secondary resist body 28 is unevenly arranged with respect to the central axis Q1 of the primary resist body 24.

In the mask for arranging the conductive pillars of the present invention, the introduction hole portion 15 constituting the arrangement through hole 12 and the holding hole portion 16 are smoothly connected to each other, and the introduction hole portion 15 for guiding the introduction of the conductive pillar 2 is masked. It was formed in the shape of a bell mouth that expanded toward the surface side of the main body 10. As described above, according to the introduction hole portion 15 formed in the shape of a bell mouth, when the conductive pillar 2 is dropped into the array through hole 12, the conductive pillar 2 in the lying posture is changed to the upright posture. The conductive pillar 2 can be introduced and guided to the array through hole 12 by dropping along the curved surface of the introduction hole portion 15. Specifically, when the position of the center of gravity of the conductive pillar 2 in the lying position is located on the array through hole 12 beyond the upper end edge of the introduction hole portion 15, one end of the conductive pillar 2 located on the array through hole 12 is inserted. It can be tilted downward with the upper end edge of the introduction hole 15 as a fulcrum. As a result, the conductive pillar 2 in the lying posture can be gradually changed from the lying posture to the upright posture. Further, at the same time as the posture is changed to the upright posture, the conductive pillar 2 can be slid into the array through hole 12 along the introduction hole portion 15. Therefore, according to the arrangement mask of the present invention, the conductive pillar 2 can be smoothly dropped into the arrangement through hole 12, so that the work of mounting the conductive pillar 2 on the work 3 can be completed in a short time.

Further, according to the straight holding hole portion 16 in which the opening diameter D1 is set to be slightly larger than the diameter of the conductive pillar 2, the conduction is guided by the introduction hole portion 15 and dropped into the array through hole 12. The sex pillar 2 can be received and positioned on the inner surface of the holding hole portion 16. Therefore, according to the arrangement mask of the present invention, the conductive pillar 2 can be accurately positioned by the holding hole portion 16, and further, the tilting and shifting movement of the conductive pillar 2 in the arrangement through hole 12 can be prevented. The conductive pillar 2 can be mounted accurately at a predetermined position on the 3.

According to the array through hole 12 provided with the escape hole portion 17 having an opening diameter D3 larger than the opening diameter D1 of the holding hole portion 16 on the lower side of the holding hole portion 16, the shafts of the conductive pillar 2 and the holding hole portion 16 are provided. The length of the engaging portion in the central direction can be made smaller than that of the array through hole 12 in which the escape hole portion 17 is not provided. Therefore, after the conductive pillar 2 is mounted on the work 3, the array mask can be separated from the work 3 with a smaller amount of movement, so that the conductive pillar 2 is not tilted or misaligned when the array mask is separated. By suppressing it, the conductive pillar 2 can be mounted more accurately at a predetermined position on the work 3. Further, when the arrangement mask is placed on the work 3, the contact area between the work 3 and the arrangement mask can be made as small as possible. As a result, it is possible to suppress damage to the array mask and the work 3 due to the placement of the array mask on the work 3, and it is possible to improve the durability of the array mask. Further, flux may be applied to the mounting position of the conductive pillar 2 on the work 3, but even in such a case, the escape hole portion 17 prevents the flux from adhering to the arrangement mask. It is possible to save the trouble of cleaning the array mask.

When the total height dimension H1 of the introduction hole portion 15 and the holding hole portion 16 is set to be the same as or larger than the height dimension H2 of the escape hole portion 17, the escape hole portion 17 is provided below the holding hole portion 16. Even if it is provided, the introduction hole portion 15 and the holding hole portion 16 having a sufficient height can be formed. Therefore, the introduction guiding action of the conductive pillar 2 in the introduction hole portion 15 and the positioning action of the conductive pillar 2 in the holding hole portion 16 can be accurately exerted.

When the height dimension H4 of the holding hole portion 16 is set to be the same as or larger than the height dimension H3 of the introduction hole portion 15, the position-retaining action of the conductive pillar 2 in the holding hole portion 16 is possible. The conductive pillar 2 can be mounted at a predetermined position on the work 3 with high accuracy.

When the curvature of the cross-sectional shape of the introduction hole portion 15 is formed so as to change in the circumferential direction of the introduction hole portion 15, the introduction guiding action of the conductive pillar 2 is greatly exerted in the portion having a small curvature, and in the portion having a large curvature. The height dimension H4 of the holding hole portion 16 can be increased to greatly exert the positioning action of the conductive pillar 2 in the holding hole portion 16. Therefore, it is possible to make it easy to partially drop the conductive pillar 2 in the circumferential direction of the introduction hole portion 15, and it is possible to make the array through hole 12 capable of accurately positioning the dropped conductive pillar 2.

When the curvature of the cross-sectional shape of the introduction hole portion 15 is formed so as to gradually change from large to small from one side edge toward the other side edge, for example, the side having the small curvature is arranged so as to be oriented in the same direction. By forming the hole 12, when the conductive pillar 2 is dropped, the squeegee is moved from the side having a small curvature to the side having a large curvature, so that the conductive pillar 2 is dropped into the array through hole 12 more quickly, and the mounting work is performed. Can be completed in a shorter time.

According to the method for manufacturing a mask for arranging conductive pillars according to the present invention, it is not necessary to separately perform a step for forming the introduction hole portion 15 into a bellmouth shape, and the arrangement passage having the bellmouth-shaped introduction hole portion 15 is provided. An array mask with holes 12 can be manufactured. Specifically, the edge portion of the growth tip of the electrocast metal, which grows over the upper end edge of the primary resist body 24, grows in a quarter arc shape. Therefore, in the electrocasting process, the bellmouth-shaped introduction hole portion 15 is formed only by electrodepositing the electrodeposited metal within a range that overcomes the upper end edge of the primary resist body 24 and does not overcome the upper end edge of the secondary resist body 28. Can be formed. Therefore, it is possible to shorten the work process in the manufacturing process of the array mask and reduce the manufacturing cost of the array mask.

In the secondary patterning step, when the central axis Q2 of the secondary resist body 28 is positioned on the same axis as the central axis Q1 of the primary resist body 24, the distance to grow over the upper end edge of the primary resist body 24. Can be made uniform in the circumferential direction, so that the cross-sectional shape of the introduction hole portion 15 can be formed to be the same in the circumferential direction. Therefore, the introduction guiding action of the conductive pillar 2 in the introduction hole portion 15 can be uniformly exerted in the circumferential direction, and the array through hole 12 capable of smoothly dropping the conductive pillar 2 from any direction can be formed.

In the secondary patterning step, when the central axis Q2 of the secondary resist body 28 is unevenly arranged with respect to the central axis Q1 of the primary resist body 24, the distance that grows over the upper end edge of the primary resist body 24 is in the circumferential direction. Therefore, the cross-sectional shape of the introduction hole portion 15 can be formed so that the curvature gradually changes from large to small in the circumferential direction. At this time, the longer the distance to overcome and grow, the smaller the curvature of the cross-sectional shape. As a result, the introduction guiding action of the conductive pillar 2 is greatly exerted on the side having a small curvature, and the height dimension H4 of the holding hole portion 16 is increased on the side having a large curvature, so that the conductive pillar in the holding hole portion 16 is exerted. The positioning action of 2 can be greatly exerted. Therefore, while the conductive pillar 2 can be easily dropped, the array through hole 12 capable of accurately positioning the dropped conductive pillar 2 can be easily formed only by performing the electroplating process.

It is a vertical sectional front view which shows the main part of the mask for arrangement of the conductive pillar which concerns on 1st Embodiment of this invention. It is a perspective view for demonstrating the whole structure of the mask for arrangement of the conductive pillars which concerns on 1st Embodiment of this invention. It is a vertical sectional front view of the mask for arrangement of the conductive pillars which concerns on 1st Embodiment of this invention. It is a figure which shows the manufacturing method of the mask for arrangement of the conductive pillar which concerns on 1st Embodiment of this invention. It is a figure which shows the manufacturing method of the mask for arrangement of the conductive pillar which concerns on 1st Embodiment of this invention. It is a vertical sectional front view which shows the main part of the mask for arrangement of the conductive pillar which concerns on 2nd Embodiment of this invention. It is a top view which shows the main part of the mask for arrangement of the conductive pillar which concerns on 2nd Embodiment of this invention. It is a figure which shows the manufacturing method of the mask for arrangement of the conductive pillar which concerns on 2nd Embodiment of this invention. It is a vertical sectional front view of the mask for arrangement of the conductive pillars which concerns on 3rd Embodiment of this invention.

(First Embodiment) FIGS. 1 to 3 show a first embodiment of a mask for arranging conductive pillars according to the present invention. It should be noted that the dimensions such as the thickness and the width in FIGS. 1 to 3 of the present embodiment do not show the actual state, but are schematically shown respectively. The same applies to other figures. The array mask (hereinafter, simply referred to as a mask) 1 is used in the mounting work of the conductive pillar 2 in forming the electrode post of the LSI chip. As shown in FIG. 3, the conductive pillar 2 is a columnar block made of copper, the diameter of which is 80 μm, and the height of which is 85 μm. In FIG. 2, reference numeral 3 is a work to which the conductive pillar 2 is mounted by the mask 1, and the work 3 is molded and sealed after mounting a plurality of semiconductor chips 5 on a base 4 of a glass epoxy substrate. Is formed. On the upper surface of the work 3, electrodes 6 which are input / output terminals are formed in a predetermined pattern so as to surround the semiconductor chip 5. After the electrode post is formed, the work 3 is diced along the dicing line shown by the alternate long and short dash line in FIG. 2 and divided into individual LSI chips.

The mask 1 includes a mask main body 10 formed by an electroforming method using an electrodeposited metal made of nickel as a material, and a frame-shaped frame 11 mounted so as to surround the mask main body 10. On the board surface of the mask main body 10, a large number of independent arrangement through holes 12 corresponding to the arrangement pattern matching the formation pattern of the electrode 6 are formed. By dropping the conductive pillar 2 into the array through hole 12, the conductive pillar 2 can be mounted at a predetermined position on the work 3. The frame body 11 reinforces the mask body 10, and is made of a material having a low coefficient of linear thermal expansion such as 42 alloy, Invar material, Super Invar material, and SUS430, which are thicker than the mask body 10. By adhering the frame body 11 to the outer peripheral edge of the mask main body 10 with an adhesive or the like, both 10 and 11 are inseparably and integrally joined. The mask body 10 can be formed of a nickel alloy such as nickel cobalt, copper, or other electrodeposited metal as a material.

As shown in FIG. 1, the array through hole 12 includes an introduction hole portion 15 that opens on the surface of the mask main body 10 and a holding hole portion 16 provided on the lower side of the introduction hole portion 15. The lower end of the 15 and the upper end of the holding hole 16 are smoothly continuous. Further, the array through hole 12 is provided with an escape hole portion 17 on the lower side of the holding hole portion 16.

The introduction hole portion 15 is formed in a bell mouth shape that expands toward the surface side of the mask main body 10, and when the conductive pillar 2 is dropped into the array through hole 12, the conductive pillar 2 is arranged in the array through hole 12. It has the function of guiding the introduction into the inside. The cross-sectional shape of the introduction hole portion 15 is the same in the circumferential direction, and the introduction guide action of the conductive pillar 2 in the introduction hole portion 15 can be uniformly exerted in the circumferential direction. The cross-sectional shape of the introduction hole portion 15 in the present embodiment is formed in the shape of a perfect circular quarter arc.

The holding hole portion 16 is formed in a straight hole shape in which the opening diameter D1 is set to be slightly larger than the diameter of the conductive pillar 2, and has an action of positioning the conductive pillar 2 dropped into the array through hole 12. Have. When the outer peripheral surface of the conductive pillar 2 comes into contact with the inner peripheral surface of the holding hole portion 16, tilting or shifting movement is prevented, and the conductive pillar 2 is positioned.

The escape hole portion 17 is formed in a straight hole shape having an opening diameter D3 larger than the opening diameter D1 of the holding hole portion 16, and the central axis P2 of the escape hole portion 17 is the central axis P1 of the holding hole portion 16. It is located on the same axis. In the present embodiment, the opening diameter D1 of the holding hole portion 16 is set to 85 μm, the opening diameter D2 at the upper end of the introduction hole portion 15 is set to 125 μm, and the opening diameter D3 of the escape hole portion 17 is set to 145 μm.

The total height dimension H1 of the introduction hole portion 15 and the holding hole portion 16 is set to be larger than the height dimension H2 of the relief hole portion 17, the height dimension H1 of the former is 50 μm, and the height dimension of the latter. H2 is 40 μm. In this way, if the height dimension H1 of the array through hole 12 is set to be larger than the height dimension H2 of the clearance hole portion 17, the height is sufficiently high even if the clearance hole portion 17 is provided under the holding hole portion 16. The introduction hole portion 15 and the holding hole portion 16 can be formed. Therefore, the introduction guiding action of the conductive pillar 2 in the introduction hole portion 15 and the positioning action of the conductive pillar 2 in the holding hole portion 16 can be accurately exerted.

The height dimension H4 of the holding hole portion 16 is set to be larger than the height dimension H3 of the introduction hole portion 15, the height dimension H3 of the latter is 20 μm, and the height dimension H4 of the former is 30 μm. In this way, when the height dimension H4 of the holding hole portion 16 is set to be larger than the height dimension H3 of the introduction hole portion 15, the positioning action of the conductive pillar 2 in the holding hole portion 16 can be more reliably exerted. can.

The mounting work of the conductive pillar 2 on the work 3 using the mask 1 is performed by the following procedure. This mounting work is performed by a dedicated arrangement device equipped with a pillar supply device, a surplus pillar recovery device, a squeegee brush, and the like. First, flux is printed and applied to the surface of the electrode 6 of the work 3 by a screen printing method. The flux activates the surface of the electrode 6 to improve the bonding strength between the electrode 6 and the conductive pillar 2 after reflow, and the conductive pillar 2 due to the adhesiveness of the flux when the conductive pillar 2 is mounted. Is applied for the purpose of temporarily fixing.

Next, the mask 1 is aligned on the work 3 so that the array through holes 12 coincide with the electrodes 6, and then the mask 1 is placed and fixed. At this time, since the contact area between the work 3 and the mask 1 can be made as small as possible by the relief hole portion 17, it is possible to prevent the mask 1 and the work 3 from being damaged by placing the mask 1 on the work 3. This makes it possible to improve the durability of the mask 1. Further, it is possible to prevent the flux from adhering to the mask 1 by the escape hole portion 17, and it is possible to save the trouble of cleaning the mask 1.

Next, a large number of conductive pillars 2 are supplied on the mask 1, the conductive pillars 2 are dispersed on the mask 1 using a squeegee brush, and one conductive pillar 2 is provided in each array through hole 12. Drop in. Dropping the conductive pillar 2 into the array through hole 12 is performed as follows. When the center of gravity of the conductive pillar 2 in the lying position distributed by the squeegee brush is located on the array through hole 12 beyond the upper end edge of the introduction hole portion 15, the conductive pillar 2 is located on the array through hole 12. One end of is tilted downward with the upper end edge of the introduction hole 15 as a fulcrum. As a result, the conductive pillar 2 in the lying posture is gradually changed from the lying posture to the upright posture. Further, at the same time as the posture is changed to the upright posture, the conductive pillar 2 slides into the array through hole 12 along the introduction hole portion 15. As a result, the conductive pillar 2 is introduced and guided by the introduction hole portion 15, and is smoothly dropped into the array through hole 12. The conductive pillar 2 dropped into the array through hole 12 is accurately positioned on the inner surface of the holding hole portion 16 in addition to being temporarily fixed by the flux.

When the dropping of the conductive pillar 2 is completed, the excess conductive pillar 2 remaining on the mask 1 is collected. Finally, the work of mounting the conductive pillar 2 on the work 3 is completed by releasing the fixing of the work 3 and the mask 1 and lifting and separating the mask 1. At this time, since the length of the engaging portion in the axial direction of the engaging portion between the conductive pillar 2 and the holding hole portion 16 is reduced by the relief hole portion 17, the work 3 to the mask 1 can be moved with a small amount of movement. Can be separated, and the conductive pillar 2 can be prevented from tilting or shifting when the mask 1 is separated.

4 and 5 show a method for manufacturing an array mask according to the first embodiment.
(Primary patterning process)
As shown in FIG. 4A, after forming the photoresist layer 22 on the entire surface of the conductive, for example, stainless steel or brass base plate 21, a circular translucent hole corresponding to the escape hole portion 17 is formed. The pattern film 23 made of a glass mask having the above is brought into close contact with each other. In this state, exposure is performed by irradiating with ultraviolet light, and each process of development and drying is performed. The photoresist layer 22 here is formed by laminating one or several sheets of negative type sheet-shaped photosensitive dry film resist by thermocompression bonding so as to have a predetermined thickness. Next, by dissolving and removing the photoresist layer 22 in the unexposed portion, as shown in FIG. 4B, a primary pattern resist 25 having a disk-shaped primary resist body 24 corresponding to the relief hole portion 17 is obtained.

(Secondary patterning process)
As shown in FIG. 4C, a photoresist layer 26 is formed on the entire surface of the matrix 21 including the formed portion of the primary pattern resist 25, and a circular translucent hole corresponding to the holding hole 16 is formed on the upper surface thereof. The pattern film 27 made of a glass mask having the above is brought into close contact with each other. At this time, the pattern film 27 is brought into close contact with the center of the translucent hole so that the center axis Q1 of the primary resist body 24 coincides with each other. In this state, exposure is performed by irradiating with ultraviolet light, and each process of development and drying is performed. The photoresist layer 26 here is the same as the method for forming the photoresist layer 22 described above. Next, by dissolving and removing the photoresist layer 26 in the unexposed portion, as shown in FIG. 4 (d), the secondary resist body 28 having the columnar secondary resist body 28 corresponding to the introduction hole portion 15 and the holding hole portion 16 is provided. The next pattern resist 29 is obtained. Since the center of the translucent hole of the pattern film 27 and the central axis Q1 of the primary resist body 24 are aligned with each other, the central axis Q2 of the columnar secondary resist body 28 is the center of the disk-shaped primary resist body 24. It is located on the same axis as the axis Q1.

(Electric casting process)
The mother die 21 is placed in a bathed electric casting tank, and as shown in FIG. 5A, electricity is applied within a range that does not get over the upper end edge of the primary resist body 24 and does not get over the upper end edge of the secondary resist body 28. The metal is electrodeposited to form an electrocasting layer 30, that is, a layer to be a mask body 10. At this time, the edge of the growth tip of the electroformed metal, which grows over the upper end edge of the primary resist body 24, grows in a quarter arc shape. The shape of the introduction hole 15 can be formed. From the above, since it is not necessary to separately perform a step for forming the introduction hole portion 15 in the shape of a bell mouth, an arrangement mask having the arrangement through hole 12 having the introduction hole portion 15 in the shape of a bell mouth can be manufactured. The work process in the mask manufacturing process can be shortened, and the manufacturing cost of the array mask can be reduced. Further, since the central axis Q2 of the secondary resist body 28 is positioned on the same axis as the central axis Q1 of the primary resist body 24, the introduction hole portion 15 having the same cross-sectional shape of the introduction hole portion 15 in the circumferential direction. Can be formed.

(Peeling process)
As shown in FIG. 5B, the electric casting layer 30 and the primary and secondary pattern resists 25 and 29 are peeled off from the master mold 21, and then the primary and secondary pattern resists 25 and 29 are melted and removed. The mask main body 10 shown in FIG. 3 is obtained. An array mask 1 is obtained by adhering the frame body 11 to the outer peripheral edge of the obtained mask body 10 with an adhesive and joining the two 10/11 in a non-separable manner.

(Second Embodiment) FIGS. 6 and 7 show a second embodiment of a mask for arranging conductive pillars according to the present invention. In the present embodiment, as shown in FIG. 6, the central axis P1 of the holding hole portion 16 is unevenly arranged with respect to the central axis P2 of the escape hole portion 17, and the cross-sectional shape of the introduction hole portion 15 is formed accordingly. The curvature is formed so as to gradually change from large to small from one side edge to the opposite side edge. More specifically, the cross-sectional shape of the introduction hole portion 15 is formed to be similar in the circumferential direction, and the curvature of the cross-sectional shape of the introduction hole portion 15 is the largest on the right side and the curvature on the left side as shown in FIG. It is the smallest, and the curvature of the middle portion from the right side to the left side of the introduction hole portion 15 gradually changes from large to small. The cross-sectional shape of the introduction hole portion 15 is formed in a perfect circular quarter arc shape. The height dimension H3 of the introduction hole portion 15 in the present embodiment is the dimension at the position where the curvature is the smallest. Since the other parts are the same as those in the first embodiment, the same members are designated by the same reference numerals and the description thereof will be omitted. The same shall apply in the following embodiments.

FIG. 8 shows a method for manufacturing an array mask according to the second embodiment. The primary patterning step in the manufacturing method of the present embodiment is the same as the method shown in FIGS. 4 (a) and 4 (b) described in the first embodiment.

(Secondary patterning process)
As shown in FIG. 8A, a photoresist layer 26 is formed on the entire surface of the matrix 21 including the formed portion of the primary pattern resist 25, and a circular translucent hole corresponding to the holding hole 16 is formed on the upper surface thereof. The pattern film 27 made of a glass mask having the above is brought into close contact with each other. At this time, the entire pattern film 27 is brought into close contact with the pattern film 27 in a state of being shifted to the right toward FIG. 8A so that the center of the translucent hole and the central axis Q1 of the primary resist body 24 are located at different positions. In this state, exposure is performed by irradiating with ultraviolet light, and each process of development and drying is performed. The photoresist layer 26 here is the same as the method for forming the photoresist layer 22 described above. Next, by dissolving and removing the photoresist layer 26 in the unexposed portion, as shown in FIG. 8 (b), the secondary resist body 28 having the columnar secondary resist body 28 corresponding to the introduction hole portion 15 and the holding hole portion 16 is provided. The next pattern resist 29 is obtained. Since the center of the translucent hole of the pattern film 27 and the central axis Q1 of the primary resist body 24 are located at different positions, the central axis Q2 of the secondary resist body 28 is the central axis Q1 of the primary resist body 24. It is biased against.

(Electric casting process)
The mother die 21 is placed in a bathed electric casting tank, and as shown in FIG. 8 (c), electric power is applied within a range that overcomes the upper end edge of the primary resist body 24 and does not get over the upper end edge of the secondary resist body 28. The metal is electrodeposited to form an electrocasting layer 30, that is, a layer to be a mask body 10. At this time, since the edge portion of the growth tip of the electroformed metal that grows over the upper end edge of the primary resist body 24 grows in a quarter arc shape, the bell is simply electrodeposited on the master mold 21. A mouse-shaped introduction hole portion 15 can be formed. Further, the longer the distance from the surface of the master mold 21 to the secondary resist body 28, the smaller the curvature of the quadrant arc, so that the edge of the growth tip of the electroformed metal that grows to the right toward FIG. 8C. The curvature of the metal is small, and the curvature of the edge of the growth tip of the electroformed metal growing on the left side is large. As a result, the array through holes 12 in which the curvature of the cross-sectional shape of the introduction hole portion 15 gradually changes from large to small in the circumferential direction can be easily formed only by performing an electrocasting step. Further, since the central axis Q2 of the secondary resist body 28 is biased with respect to the central axis Q1 of the primary resist body 24, the central axis P1 of the holding hole portion 16 is displaced with respect to the central axis P2 of the escape hole portion 17. It can be formed in an unevenly arranged state.

(Peeling process)
As shown in FIG. 8D, the electric casting layer 30 and the primary and secondary pattern resists 25 and 29 are peeled off from the master mold 21, and then the primary and secondary pattern resists 25 and 29 are melted and removed. The mask main body 10 shown in FIG. 6 is obtained. An array mask 1 is obtained by adhering the frame body 11 to the outer peripheral edge of the obtained mask body 10 with an adhesive and joining the two 10/11 in a non-separable manner.

As described above, when the cross-sectional shape of the introduction hole portion 15 is formed so as to gradually change from large to small from one side edge toward the other side edge facing each other in the circumferential direction, the conductive pillar 2 is formed on the side having a small curvature. On the side with a large curvature, the height dimension H4 of the holding hole portion 16 can be increased to greatly exert the positioning action of the conductive pillar 2 in the holding hole portion 16. Therefore, it is possible to make it easy to partially drop the conductive pillar 2 in the circumferential direction of the introduction hole portion 15, and it is possible to make the array through hole 12 capable of accurately positioning the dropped conductive pillar 2. Further, by forming the array through holes 12 so that the side having a small curvature is directed in the same direction, the squeegee is moved from the side having a small curvature to the side having a large curvature when the conductive pillar 2 is dropped, so that the squeegee can be moved more quickly. By dropping the conductive pillar 2 into the array through hole 12, the mounting work can be completed in a shorter time.

In the present embodiment, the curvature is formed so as to gradually change from large to small from one side edge to the other opposite side edge, but the portion having a large curvature in the circumferential direction of the introduction hole portion 15 and the curvature are small. The portions may be formed smoothly and alternately. It should be noted that the portion having a large curvature and the portion having a small curvature may be formed so that the curvature gradually changes from large to small or from small to large. In this case, in the primary patterning step, the primary resist body 24 corresponding to the escape hole portion 17 is formed by using the pattern film 23 made of a glass mask in which the light-transmitting holes corresponding to the escape hole portion 17 are formed in a petal shape. The primary pattern resist 25 to have is formed. Subsequent steps are the same as in the first embodiment. By forming the petal-shaped primary resist body 24 in this way, the timing at which the electrodeposited metal gets over the upper end edge of the primary resist body 24 during the electrocasting process and comes into contact with the secondary resist body 28 is partially different. be able to. As a result, the curvature of the edge portion of the growth tip of the electrocast metal that has previously contacted the secondary resist body 28 can be increased, and the curvature of the edge portion of the growth tip of the other portion can be reduced.

The array mask (metal mask) of the present embodiment can also be applied to a metal mask such as an array mask of conductive balls and a screen printing mask forming a print layer of a conductive paste. It should be noted that the same applies to each of the other embodiments.

(Third Embodiment) FIG. 9 shows a third embodiment of a mask for arranging conductive pillars according to the present invention. In the first embodiment, as shown in FIG. 9, a plurality of support protrusions 35 formed in columns on the lower surface of the mask main body 10 are integrally provided so as to avoid the escape hole portion 17. Different from. The support protrusion 35 may be formed of the same metal material as the mask body 10, or may be formed of another metal material. It can also be formed of a non-magnetic material such as copper or resin. Since the support protrusion 35 is provided on the lower surface of the mask body 10 in this way, it is possible to avoid contact between the work 3 and the mask 1 as much as possible, and the mask 1 and the mask 1 by placing the mask 1 on the work 3 can be avoided as much as possible. It is possible to further suppress damage to the work 3. Further, the durability of the mask 1 can be further improved.

In the above embodiment, the support protrusions 35 are provided so as to avoid the escape hole portion 17, but they may be provided at equal intervals at positions corresponding to the dicing line of the work 3 shown by the alternate long and short dash line in FIG. It may be provided only at the position corresponding to the intersection of the dicing lines. The support protrusion 35 is not limited to a columnar shape, but can be formed in a rib shape. In the case of forming in a rib shape, a group of support protrusions 35 arranged in parallel may be formed, or the support protrusions 35 may be formed in a grid pattern.

As described above, according to the mask for arranging the conductive pillars according to each of the above embodiments, the conductive pillars 2 are introduced and guided by the introduction hole portion 15 formed in the shape of a bell mouth, and the conductive pillars 2 are arranged through the arrangement. Since it can be smoothly dropped into the hole 12, the work of mounting the conductive pillar 2 on the work 3 can be completed in a short time. Further, since the conductive pillar 2 dropped into the array through hole 12 can be positioned by the straight hole-shaped holding hole portion 16 to prevent the conductive pillar 2 from tilting or shifting in the array through hole 12, the work can be prevented. The conductive pillar 2 can be mounted accurately at a predetermined position on the 3.

In each of the above embodiments, the cross-sectional shape of the introduction hole portion 15 is formed in a quarter arc shape, but it may be an elliptical quarter arc shape or a partially outer protrusion arc shape. The escape hole portion 17 is not limited to a straight hole shape, but can be formed into a truncated cone hole shape or a stepped hole shape. In the case of forming a stepped hole shape, the primary resist body 24 may be formed in a stepped shape by dividing it into two steps.

2 Conductive pillar (object)
3 Work 10 Mask body 12 Through hole 15 Introducing hole 16 Holding hole 17 Escape hole 21 Mother mold 24 Primary resist body 25 Primary pattern resist 28 Secondary resist body 29 Secondary pattern resist 30 Electrocast layer D1 Opening diameter D3 Open Diameter H1 Total height of introduction hole and holding hole H2 Height of escape hole H3 Height of introduction hole H4 Height of holding hole Q1 Central axis of primary resist Q2 Secondary resist Central axis of

Claims (3)

A metal mask provided with through holes (12) corresponding to a predetermined pattern.
The through hole (12) includes an introduction hole portion (15) opened on the surface of the mask main body (10) and a holding hole portion (16) provided under the introduction hole portion (15). ,
The height dimension of the holding hole portion (16) is set to a different height between one side edge and the other side edge.
In a cross-sectional view of the mask body (10) in the thickness direction, the inner surface of one side edge of the introduction hole portion (15) faces the inner surface of the other side edge of the holding hole portion (16). Metal mask. In a cross-sectional view of the mask body (10) in the thickness direction, the inner surface of one side edge of the introduction hole (15) is the surface of the mask body (10) as it goes from the front surface to the back surface of the mask body (10). The metal mask according to claim 1, wherein the metal mask has a surface that increases the distance from the surface. The metal mask according to claim 2, wherein the side having the surface of one side edge of the introduction hole portion (15) is oriented in the same direction in a plan view of the mask body (10).

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