JP7175354B2 - Metal mask - Google Patents

Description

The present invention relates to a metal mask provided with through holes corresponding to a predetermined pattern for forming (mounting, arranging, printing, applying) objects (pillars, balls, paste, etc.) at predetermined positions on a workpiece.

As an example of a metal mask, an arrangement mask for mounting conductive balls made of solder at predetermined positions on a work is known, for example, in Japanese Unexamined Patent Application Publication No. 2002-100000. The arrangement mask disclosed in Patent Document 1 has a plurality of openings into which the conductive balls are dropped. The openings are provided so as to correspond to the formation pattern of the electrode pads of the substrate (work). A sloped 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 slopes gently downward toward the opening. At the time of dropping, a large number of conductive balls are supplied onto the array mask and dispersed with a squeegee brush or the like, so that the ball guiding portion guides the conductive balls toward the opening, allowing the conductive balls to move smoothly. You can drop it into the opening.

JP 2011-44616 A

In recent years, in surface-mounted packaged electronic devices, etc., the density of electrode formation patterns for connecting to circuit boards has been increasing, and instead of conventional conductive balls, higher aspect ratio (higher Cylindrical conductive pillars are being adopted, which allow narrowing of the mounting interval with the height/diameter ratio). In the arrangement mask of Patent Document 1, the structures of the openings and the ball guiding portions are optimized so that the conductive balls can be dropped smoothly. However, even if the structure of the arrangement mask of Patent Document 1 is applied to a mask for arrangement of columnar conductive pillars, the same effect cannot be obtained. That is, in order for the columnar conductive pillars to drop into the openings (arranged through holes), one end of the conductive pillars must face the openings. Additionally, the conductive pillar must slide down the ball guide with one end facing the opening. However, it is difficult for the conductive pillar to slide down on the ball guiding portion formed with the gently downwardly inclined surface. In addition, when the peripheral surface of the conductive pillar in a lying posture rolls down the ball guiding portion while facing the opening, the conductive pillar cannot fall into the opening and blocks the opening. Can't drop conductive pillars.

An object of the present invention is to allow objects such as conductive pillars to smoothly pass through the through holes so that the object forming operation can be completed in a short period of time and the objects can be accurately formed at predetermined positions on the workpiece. To provide a metal mask.

The present invention is directed to an arraying mask in which cylindrical conductive pillars 2 are dropped into array through holes 12 corresponding to a predetermined array pattern, and conductive pillars 2 are mounted at predetermined positions on a workpiece 3 . The array through hole 12 includes an introduction hole portion 15 that opens on the surface of the mask body 10 and introduces and guides the conductive pillars 2 into the array through hole 12. 2, and the lower end of the introduction hole 15 and the upper end of the holding hole 16 are smoothly continuous. The introduction hole portion 15 is formed in a bellmouth shape that widens toward the surface side of the mask body 10 , and the holding hole portion 16 has an opening diameter D1 larger than the diameter of the conductive pillar 2 . It is characterized by being formed with a straight hole set slightly large.

The arrangement through holes 12 can be configured to have escape holes 17 having an opening diameter D3 larger than the opening diameter D1 of the holding holes 16 below the holding holes 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 not. 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 latter height dimension H4 is set equal to or larger than the former height dimension H3.

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

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

The present invention is directed to a method of manufacturing an array mask in which conductive pillars 2 are placed at predetermined positions on a workpiece 3 by placing cylindrical conductive pillars 2 into array through holes 12 corresponding to a predetermined array pattern. and In the method of manufacturing the array mask, a primary patterning step of providing a primary pattern resist 25 having a primary resist body 24 corresponding to the escape hole 17 on the surface of the master mold 21; A secondary patterning step of providing a secondary pattern resist 29 having a secondary resist body 28 corresponding to the holes 15 and the holding holes 16, and an electroformed layer 30 by electrodepositing an electrodeposited metal on the master mold 21. and an electroforming process to form the In the electroforming process, an electrodeposited metal is electrodeposited in a range that exceeds the upper edge of the primary resist body 24 and does not extend over the upper edge of the secondary resist body 28 to form the bellmouth-shaped introduction hole portion 15. Characterized by

In the secondary patterning step, the secondary pattern resist 29 is provided with the central axis Q2 of the secondary resist body 28 coaxial with the central axis Q1 of the primary resist body 24 .

In the secondary patterning step, the secondary pattern resist 29 is provided with the central axis Q2 of the secondary resist body 28 being offset 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 and the holding hole portion 16 forming the through holes 12 are smoothly connected to each other, and the introduction hole portion 15 for introducing and guiding the conductive pillars 2 is formed in the mask. It is formed in a bell mouth shape expanding toward the surface side of the main body 10. - 特許庁As described above, according to the introduction hole portion 15 formed in the shape of a bell mouth, when the conductive pillar 2 is lowered into the array through hole 12, the conductive pillar 2 is changed from the lying posture to the upright posture. The conductive pillars 2 can be introduced and guided into the array through holes 12 by dropping along the curved surface of the introduction hole portion 15 . Specifically, when the center of gravity of the conductive pillar 2 in the recumbent posture is positioned above the array through hole 12 beyond the upper edge of the introduction hole portion 15, one end of the conductive pillar 2 positioned above the array through hole 12 is pushed. It can be tilted downward with the upper edge of the introduction hole portion 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. Furthermore, the conductive pillar 2 can be slid into the array through hole 12 along the introduction hole portion 15 at the same time as the posture is changed to the upright posture. Therefore, according to the aligning mask of the present invention, the conductive pillars 2 can be smoothly dropped into the aligning holes 12, so that the work of mounting the conductive pillars 2 onto the workpiece 3 can be completed in a short time.

Further, according to the straight holding hole portion 16 whose opening diameter D1 is set slightly larger than the diameter of the conductive pillar 2, the conductive material introduced and guided by the introduction hole portion 15 and dropped into the array through hole 12 The magnetic pillar 2 can be received and positioned on the inner surface of the holding hole portion 16 . Therefore, according to the arraying mask of the present invention, the conductive pillars 2 can be accurately positioned by the holding holes 16, and furthermore, the tilting and displacement of the conductive pillars 2 in the arraying through holes 12 can be prevented. The conductive pillar 2 can be mounted at a predetermined position on the 3 with high accuracy.

According to the arrangement through holes 12 provided with the escape hole portion 17 having the opening diameter D3 larger than the opening diameter D1 of the holding hole portion 16 below the holding hole portion 16, the axis of the conductive pillar 2 and the holding hole portion 16 The length of the engagement portion in the central direction can be made smaller than that of the arrayed through holes 12 in which the escape hole portion 17 is not provided. Therefore, after the conductive pillars 2 are mounted on the work 3, the aligning mask can be separated from the work 3 with a smaller amount of movement. By suppressing this, the conductive pillar 2 can be mounted at a predetermined position on the workpiece 3 with higher accuracy. In addition, when the aligning mask is placed on the work 3, the contact area between the work 3 and the aligning mask can be made as small as possible. As a result, damage to the array mask and the work 3 caused by placing the array mask on the work 3 can be suppressed, and the durability of the array mask can be improved. Furthermore, flux may be applied to the mounting positions of the conductive pillars 2 on the workpiece 3. Even in such a case, the escape holes 17 prevent the flux from adhering to the array 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 equal to or larger than the height dimension H2 of the escape hole portion 17, the escape hole portion 17 is formed below the holding hole portion 16. Even if they are provided, the introduction hole portion 15 and the holding hole portion 16 with sufficient height can be formed. Therefore, it is possible to appropriately exhibit 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 .

If the height dimension H4 of the holding hole portion 16 is set equal to or larger than the height dimension H3 of the introduction hole portion 15, the position retention action of the conductive pillar 2 in the holding hole portion 16 can be maximized. It is possible to exert a large effect, and the conductive pillar 2 can be mounted at a predetermined position on the work 3 with high accuracy.

If 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 and guiding action of the conductive pillar 2 can be greatly exhibited in the portion with a small curvature, and in the portion with a large curvature. By increasing the height dimension H4 of the holding hole portion 16, the positioning effect of the conductive pillar 2 in the holding hole portion 16 can be greatly exhibited. Therefore, the conductive pillars 2 can be easily dropped partially in the circumferential direction of the introduction hole portion 15, and furthermore, the arranged through holes 12 can be formed in which the dropped conductive pillars 2 can be accurately positioned.

If the curvature of the cross-sectional shape of the introduction hole portion 15 is formed so as to gradually change from large to small toward the opposite side edge from one side edge, for example, the side with the smaller curvature can be aligned in the same direction. By forming the holes 12, when the conductive pillars 2 are dropped, the squeegee is moved from the small curvature side to the large curvature side to drop the conductive pillars 2 into the array through holes 12 more quickly, thereby performing the mounting work. can be completed in a shorter time.

According to the method of manufacturing a mask for arranging conductive pillars according to the present invention, there is no need to perform a separate step for forming the introduction hole 15 in the shape of a bell mouth, and an arrangement through hole having the introduction hole 15 in the shape of a bell mouth can be obtained. An alignment mask with holes 12 can be manufactured. More specifically, the edge of the growth tip of the electroformed metal growing over the upper edge of the primary resist body 24 grows in a quarter arc shape. Therefore, in the electroforming process, the bellmouth-shaped introduction hole portion 15 can be formed by simply electrodepositing the electrodeposited metal in a range that exceeds the upper edge of the primary resist body 24 and does not extend over the upper edge of the secondary resist body 28 . can be formed. Therefore, it is possible to reduce the manufacturing cost of the array mask by shortening the work steps in the manufacturing process of the array mask.

In the secondary patterning process, when the central axis Q2 of the secondary resist body 28 is positioned coaxially with the central axis Q1 of the primary resist body 24, the distance that grows beyond the upper edge of the primary resist body 24 can be made uniform in the circumferential direction, the cross-sectional shape of the introduction hole portion 15 can be formed to be the same in the circumferential direction. Therefore, the conductive pillars 2 can be introduced and guided in the introduction hole portion 15 uniformly in the circumferential direction, and the array through holes 12 can be formed in which the conductive pillars 2 can be smoothly dropped from any direction.

In the secondary patterning process, when the central axis Q2 of the secondary resist body 28 is arranged to be offset from the central axis Q1 of the primary resist body 24, the distance of growth beyond the upper edge of the primary resist body 24 is measured 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 curvature of the cross-sectional shape becomes smaller as the distance of overcoming and growing becomes longer. As a result, the guiding action of the conductive pillar 2 is greatly exhibited on the side with a small curvature, and the height dimension H4 of the holding hole 16 is increased on the side with a large curvature. 2 can be greatly exhibited. Therefore, it is possible to easily form the array through-holes 12 in which the conductive pillars 2 can be accurately positioned while the conductive pillars 2 are easily dropped, simply by performing the electroforming process.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical cross-sectional front view showing a main part of a mask for arranging conductive pillars according to a first embodiment of the present invention; 1 is a perspective view for explaining the overall structure of a mask for arranging conductive pillars according to a first embodiment of the present invention; FIG. 1 is a longitudinal front view of a mask for arranging conductive pillars according to a first embodiment of the present invention; FIG. FIG. 4 is a diagram showing a method of manufacturing a mask for arranging conductive pillars according to the first embodiment of the present invention; FIG. 4 is a diagram showing a method of manufacturing a mask for arranging conductive pillars according to the first embodiment of the present invention; FIG. 6 is a longitudinal front view showing a main part of a mask for arranging conductive pillars according to a second embodiment of the present invention; FIG. 7 is a plan view showing a main part of a mask for arranging conductive pillars according to a second embodiment of the present invention; It is a figure which shows the manufacturing method of the mask for arrangement|sequence of a conductive pillar based on 2nd Embodiment of this invention. FIG. 10 is a longitudinal front view of a mask for arranging conductive pillars according to a third embodiment of the present invention;

(First Embodiment) FIGS. 1 to 3 show a first embodiment of a mask for arranging conductive pillars according to the present invention. Note that the dimensions such as thickness and width in FIGS. 1 to 3 of the present embodiment do not show the actual state, but are shown schematically. The same applies to other drawings. An array mask (hereinafter simply referred to as a mask) 1 is used in the work of mounting conductive pillars 2 in forming electrode posts of an LSI chip. As shown in FIG. 3, the conductive pillar 2 is a cylindrical block made of copper and has a diameter of 80 μm and a height of 85 μm. In FIG. 2, reference numeral 3 denotes a work on which conductive pillars 2 are to be mounted by means of a mask 1. This work 3 is molded after mounting a plurality of semiconductor chips 5 on a base 4 of a glass epoxy substrate. formed by Electrodes 6 serving as input/output terminals are formed in a predetermined pattern on the upper surface of the workpiece 3 so as to surround the semiconductor chip 5 . After forming the electrode posts, the workpiece 3 is diced along dicing lines indicated by dashed lines in FIG. 2 to be divided into individual LSI chips.

The mask 1 consists of a mask body 10 formed by electroforming using an electrodeposited metal made of nickel, and a frame-like frame 11 mounted so as to surround the mask body 10 . A large number of independent arrayed through holes 12 are formed in the board surface of the mask main body 10 so as to correspond to the array pattern that matches the formation pattern of the electrodes 6 . By dropping the conductive pillars 2 into the array through holes 12 , the conductive pillars 2 can be mounted at predetermined positions on the workpiece 3 . The frame 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 bonding the frame body 11 to the outer peripheral edge of the mask body 10 with an adhesive or the like, both 10 and 11 are inseparably and integrally joined. Note that the mask body 10 can be formed using a nickel alloy such as nickel-cobalt, copper, or other electrodeposited metal as a material.

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

The introduction hole portion 15 is formed in a bell mouth shape that widens toward the surface side of the mask body 10 , and when the conductive pillars 2 are dropped into the array through holes 12 , the conductive pillars 2 are inserted into the array through holes 12 . It has the effect of guiding the introduction into the inside. The cross-sectional shape of the introduction hole portion 15 is the same in the circumferential direction, so that the introduction guide function of the conductive pillar 2 in the introduction hole portion 15 can be exhibited uniformly 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 quarter arc of a perfect circle.

The holding hole portion 16 is formed in a straight hole shape with an opening diameter D1 set slightly larger than the diameter of the conductive pillar 2, and functions to position the conductive pillar 2 dropped into the array through hole 12. have The contact of the outer peripheral surface of the conductive pillar 2 with the inner peripheral surface of the holding hole 16 prevents the slanting and shifting movement, 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 aligned with the central axis P1 of the holding hole portion 16. located on the same axis. In this embodiment, the opening diameter D1 of the holding hole portion 16 is set to 85 μm, the opening diameter D2 of 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 is 50 μm. H2 is 40 μm. By setting the height dimension H1 of the array through holes 12 to be larger than the height dimension H2 of the escape hole portion 17 in this way, even when the escape hole portion 17 is provided below the holding hole portion 16, the height is sufficiently high. The introduction hole portion 15 and the holding hole portion 16 can be formed. Therefore, it is possible to appropriately exhibit 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 .

The height dimension H4 of the holding hole portion 16 is set 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. By setting the height dimension H4 of the holding hole portion 16 to be larger than the height dimension H3 of the introduction hole portion 15 in this way, the positioning action of the conductive pillar 2 in the holding hole portion 16 can be exhibited more reliably. can.

The operation of mounting the conductive pillar 2 on the workpiece 3 using the mask 1 is performed in the following procedure. This mounting work is performed by a dedicated arranging device equipped with a pillar feeding device, a surplus pillar collecting device, a squeegee brush, and the like. First, the surface of the electrode 6 of the workpiece 3 is coated with flux by screen printing. The purpose of the flux is to activate the surface of the electrode 6 and improve the bonding strength between the electrode 6 and the conductive pillar 2 after reflow. It is applied for the purpose of temporarily fixing the

Next, after aligning the mask 1 on the workpiece 3 so that the through-holes 12 are aligned with the electrodes 6, 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, the mask 1 and the work 3 can be prevented from being damaged when the mask 1 is placed on the work 3. , and the durability of the mask 1 can be improved. In addition, the flux is prevented from adhering to the mask 1 by the relief hole portion 17, and the trouble of cleaning the mask 1 can be saved.

Next, a large number of conductive pillars 2 are provided on the mask 1 , and a squeegee brush is used to disperse the conductive pillars 2 on the mask 1 so that the conductive pillars 2 are arranged one by one in each of the array through holes 12 . drop in. Dropping the conductive pillars 2 into the array through-holes 12 is performed as follows. When the center of gravity of the conductive pillars 2 in the lying posture dispersed by the squeegee brush is positioned above the array through-holes 12 beyond the upper edge of the introduction hole portion 15, the conductive pillars 2 are positioned above the array through-holes 12. One end of the tilts downward with the upper edge of the introduction hole portion 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, the conductive pillar 2 slides along the introduction hole portion 15 into the array through hole 12 at the same time as the posture is changed to the upright posture. As a result, the conductive pillars 2 are introduced and guided by the introduction hole portions 15 and are smoothly dropped into the array through holes 12 . The conductive pillars 2 dropped into the array through-holes 12 are accurately positioned on the inner surfaces of the holding holes 16 in addition to being temporarily fixed by the flux.

When the dropping of the conductive pillars 2 is completed, the excessive conductive pillars 2 remaining on the mask 1 are collected. Finally, the work 3 and the mask 1 are released from the fixing, and the mask 1 is lifted and separated, thereby completing the work of mounting the conductive pillars 2 on the work 3 . 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 escape hole portion 17, the mask 1 can be removed from the work 3 with a small amount of movement. can be separated, and it is possible to prevent the conductive pillars 2 from being tilted or misaligned when the mask 1 is separated.

4 and 5 show the method of manufacturing the array mask according to the first embodiment.
(Primary patterning process)
As shown in FIG. 4( a ), a photoresist layer 22 is formed on the entire surface of a matrix 21 made of, for example, stainless steel or brass. A pattern film 23 made of a glass mask having In this state, exposure is performed by irradiating ultraviolet rays, and each processing such as development and drying is performed. The photoresist layer 22 here is formed by laminating one or several sheets of negative type photosensitive dry film resist by thermocompression bonding so as to have a predetermined thickness. Next, by dissolving and removing the unexposed portions of the photoresist layer 22, a primary pattern resist 25 having a disk-shaped primary resist body 24 corresponding to the escape hole 17 is obtained as shown in FIG. 4(b).

(Secondary patterning step)
As shown in FIG. 4(c), a photoresist layer 26 is formed on the entire surface of the master mold 21 including the portion where the primary pattern resist 25 is to be formed. A pattern film 27 made of a glass mask having At this time, the pattern film 27 is adhered so that the center of the transparent hole and the central axis Q1 of the primary resist body 24 are aligned. In this state, exposure is performed by irradiating ultraviolet rays, and each processing such as development and drying is performed. The photoresist layer 26 here is formed by the same method as the photoresist layer 22 described above. Next, by dissolving and removing the unexposed portions of the photoresist layer 26, as shown in FIG. A next pattern resist 29 is obtained. Since the center of the transparent hole of the pattern film 27 and the central axis Q1 of the primary resist body 24 are aligned, the central axis Q2 of the cylindrical secondary resist body 28 coincides with the center of the disk-shaped primary resist body 24. It is located coaxially with the axis Q1.

(Electroforming process)
The master mold 21 is placed in a prepared electroforming tank, and as shown in FIG. A deposition metal is electrodeposited to form an electroformed layer 30 , that is, a layer that will become the mask body 10 . At this time, since the edge of the growth tip of the electroformed metal growing over the upper edge of the primary resist body 24 grows in a quarter-arc shape, the bell mouth can be obtained simply by electrodepositing the electrodeposited metal on the matrix 21 . It is possible to form an introduction hole portion 15 having a shape. As described above, it is possible to manufacture an arraying mask provided with the array through-holes 12 having the bell-mouthed introduction holes 15 without performing a separate step for forming the introduction holes 15 in a bell-mouth shape. By shortening the work steps in the mask manufacturing process, the manufacturing cost of the array mask can be reduced. In addition, since the central axis Q2 of the secondary resist body 28 is positioned coaxially with the central axis Q1 of the primary resist body 24, the cross-sectional shape of the introduction hole part 15 is the same in the circumferential direction. can be formed.

(Peeling process)
As shown in FIG. 5(b), the electroformed layer 30 and the primary and secondary pattern resists 25 and 29 are removed from the master mold 21, and then the primary and secondary pattern resists 25 and 29 are dissolved and removed. Thus, the mask body 10 shown in FIG. 3 is obtained. A frame 11 is adhered to the outer periphery of the obtained mask main body 10 with an adhesive, and the mask 1 for arraying is obtained by joining both 10 and 11 inseparably and integrally.

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

FIG. 8 shows a method of manufacturing an array mask according to the second embodiment. The primary patterning step in the manufacturing method of this embodiment is the same as the method shown in FIGS. 4A and 4B described in the first embodiment.

(Secondary patterning step)
As shown in FIG. 8A, a photoresist layer 26 is formed on the entire surface of the master mold 21 including the portion where the primary pattern resist 25 is to be formed, and circular translucent holes corresponding to the holding holes 16 are formed on the upper surface. A pattern film 27 made of a glass mask having At this time, the entire pattern film 27 is brought into close contact with the pattern film 27 shifted to the right side as viewed in FIG. In this state, exposure is performed by irradiating ultraviolet rays, and each processing such as development and drying is performed. The photoresist layer 26 here is formed by the same method as the photoresist layer 22 described above. Next, by dissolving and removing the unexposed portions of the photoresist layer 26, as shown in FIG. A next pattern resist 29 is obtained. Since the center of the light-transmitting hole of the pattern film 27 and the central axis Q1 of the primary resist body 24 are positioned at different positions, the central axis Q2 of the secondary resist body 28 coincides with the central axis Q1 of the primary resist body 24. biased against.

(Electroforming process)
The master mold 21 is placed in a prepared electroforming tank, and as shown in FIG. A deposition metal is electrodeposited to form an electroformed layer 30 , that is, a layer that will become the mask body 10 . At this time, since the edge of the growth tip of the electroformed metal that grows over the upper edge of the primary resist body 24 grows in a quarter arc shape, the electrodeposition of the electrodeposited metal on the master mold 21 is enough to obtain a belt. A mouth-shaped introduction hole 15 can be formed. Also, the longer the distance from the surface of the matrix 21 to the secondary resist body 28, the smaller the curvature of the quarter arc. has a small curvature, and the edge of the growth tip of the electroformed metal growing on the left side has a large curvature. As a result, the through hole array 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 the electroforming process. 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 shifted from the central axis P2 of the relief hole portion 17. It can be formed in a state of being eccentrically arranged.

(Peeling process)
As shown in FIG. 8(d), the electroformed layer 30 and the primary and secondary pattern resists 25 and 29 are removed from the master mold 21, and then the primary and secondary pattern resists 25 and 29 are dissolved and removed. Thus, the mask body 10 shown in FIG. 6 is obtained. A frame 11 is adhered to the outer periphery of the obtained mask main body 10 with an adhesive, and the mask 1 for arraying is obtained by joining both 10 and 11 inseparably and integrally.

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 in the circumferential direction from one side edge toward the opposite side edge, the conductive pillar 2 , and by increasing the height dimension H4 of the holding hole 16 on the side with a large curvature, the positioning action of the conductive pillar 2 in the holding hole 16 can be largely exhibited. Therefore, the conductive pillars 2 can be easily dropped partially in the circumferential direction of the introduction hole portion 15, and furthermore, the arranged through holes 12 can be formed in which the dropped conductive pillars 2 can be accurately positioned. In addition, by forming the array through holes 12 so that the side with the smaller curvature points in the same direction, the squeegee can be moved from the side with the smaller curvature toward the side with the larger curvature when the conductive pillar 2 is dropped, thereby making the squeegee move more quickly. By dropping the conductive pillars 2 into the array through holes 12, the mounting work can be completed in a shorter time.

In the present embodiment, the curvature is formed so that it gradually changes from large to small from one side edge to the opposite side edge. The portions may alternate smoothly. It should be noted that the portion between the large curvature portion and the small curvature portion should be formed such that the curvature gradually changes from large to small or from small to large. In this case, in the primary patterning process, a pattern film 23 made of a glass mask having petal-like translucent holes corresponding to the escape holes 17 is used to form a primary resist body 24 corresponding to the escape holes 17. A primary pattern resist 25 is formed. Subsequent steps are the same as in the first embodiment. By forming the petal-shaped primary resist body 24 in this manner, the electrodeposited metal crosses over the upper edge of the primary resist body 24 and contacts the secondary resist body 28 during the electroforming process, so that the timing of contact with the secondary resist body 28 is partially varied. be able to. As a result, the curvature of the edge of the growth tip of the electroformed metal that has come into contact with the secondary resist body 28 first can be increased, and the curvature of the edge of the growth tip of the other portion can be reduced.

The arranging mask (metal mask) of the present embodiment can also be applied to a metal mask such as a conductive ball arranging mask and a screen printing mask for forming a printed layer of a conductive paste. In addition, it supplements that it is the same also in other each embodiment.

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

In the above-described embodiment, the support projections 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 lines of the workpiece 3 indicated by the dashed-dotted lines in FIG. They may be provided only at positions corresponding to intersections of dicing lines. The support protrusion 35 is not limited to a columnar shape, and may be formed in a rib shape. When forming in a rib shape, a group of supporting projections 35 arranged in parallel may be formed, or the supporting projections 35 may be formed in a grid pattern.

As described above, according to the conductive pillar arranging mask according to each of the above-described embodiments, the conductive pillars 2 are introduced and guided through the introduction holes 15 formed in the shape of a bell mouth, and the conductive pillars 2 are arranged and passed through. Since the conductive pillar 2 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. In addition, since the conductive pillars 2 dropped into the array through-holes 12 can be positioned by the straight hole-shaped holding holes 16 to prevent the conductive pillars 2 from tilting or shifting within the array through-holes 12, the work can be The conductive pillar 2 can be mounted at a predetermined position on the 3 with high accuracy.

In each of the above-described embodiments, the introduction hole portion 15 has a cross-sectional shape of a quarter arc, but it may be a quarter arc of an ellipse or a partially convex arc. The relief hole portion 17 is not limited to a straight hole shape, and can be formed in a truncated cone shape or a stepped hole shape. When forming a stepped hole, the primary resist body 24 may be divided into two steps and formed stepwise.

2 Conductive pillar (object)
3 Workpiece 10 Mask main body 12 Through hole 15 Introduction hole 16 Holding hole 17 Escape hole 21 Master mold 24 Primary resist body 25 Primary pattern resist 28 Secondary resist body 29 Secondary pattern resist 30 Electroforming 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 Q2 of primary resist body Secondary resist body 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) that opens on the surface of the mask body (10) and a holding hole portion (16) that is provided below the introduction hole portion (15). , the lower end of the introduction hole (15) and the upper end of the holding hole (16) are smoothly continuous,
The height dimension of the holding hole (16) is set to be different between one side edge and the other side edge,
In a cross-sectional view in the thickness direction of the mask body (10), the inner surface of one side edge of the introduction hole (15) faces the inner surface of the other side edge of the holding hole (16). metal mask. In a cross-sectional view of the mask main body (10) in the thickness direction, the inner surface of one side edge of the introduction hole (15) gradually increases toward the other side edge of the holding hole (16) . 2. A metal mask according to claim 1, having faces with increasing distance from the surface. 3. The metal mask according to claim 2, wherein, in a plan view of the mask body (10), the side having the surface of one side edge of the introduction hole (15) faces in the same direction.

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