JP4933131B2 - Ball mounting apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ball mounting apparatus with a mask capable of removing stray balls. <P>SOLUTION: The ball mounting apparatus 7 has a mask 110 having a plurality of holes 111 and a ball feeder unit 74. The feeder unit 74 feeds microballs B onto the mask 110 laid on a substrate 100 to mount the balls B on the substrate 100 through the plurality of holes 111 of the mask 110. The mask 110 has a plurality of linearly extending slender projections 112 on the downside, keeping away from the plurality of holes 111, The slender projections 112 are provided in one direction only. The apparatus 7 wipes to clean the downside of the mask 110 by a cleaning unit 140 moving in one direction with contacting with the downside of the mask 110 to remove flux or stray balls, etc. deposited to the downside of the mask 110. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

The present invention relates to an apparatus and method for mounting a micro ball having a diameter of, for example, 1 mm or less at a predetermined position on a substrate, and in particular, when manufacturing a semiconductor device, an optical device, an integrated circuit device, a display device, or the like. The present invention relates to an apparatus and a method suitable for mounting a conductive minute ball on a substrate.

  As a method for mounting conductive microballs on a semiconductor wafer or an electronic circuit board, a method using a mask in which an opening enough to penetrate microparticles is used. Patent Document 1 discloses a mask having soft magnetism for arranging conductive balls in a predetermined arrangement pattern on a wafer composed of a plurality of regularly arranged semiconductor chips.

  The mask includes an opening through which a conductive ball can be inserted and a non-opening around the opening. The opening is formed corresponding to the electrode arrangement pattern of the substrate (wafer). The wafer is coated with a flux for fixing the electrodes and the conductive balls later by reflow processing. Therefore, adhesion of the flux to the mask may cause a failure such as poor conductivity or short circuit. For this reason, the concave portion is formed on the lower surface (surface on the wafer side) of the non-opening portion of the mask so as to form a relief (concave portion) on which the flux hardly adheres to the mask when the mask is superimposed on the wafer. A protrusion protruding from the wafer toward the wafer is formed. The convex portion is outside a region where a plurality of openings for arranging a plurality of conductive balls on each semiconductor chip included in the wafer are densely arranged (a plurality of units constituting one unit constituting a predetermined array pattern). It is formed in a frame shape (lattice shape) around the area including the opening.

This mask is used in an arrangement device having a permanent magnet below the wafer mounting portion. That is, this array device is used in a state where the vacuum pump is operated to fix the wafer to the mounting portion, the mask and the wafer are positioned, and the mask is closely fixed to the wafer by the magnetic force of the permanent magnet. .
JP 2006-5276 A

  By the way, when manufacturing precision devices such as semiconductor devices, optical devices, integrated circuit devices, or display devices, ball mounting is used for the purpose of mounting conductive micro-balls at predetermined positions on a substrate such as a wafer. In an apparatus (array apparatus), it is required to mount conductive microballs only at predetermined positions on the substrate with the highest possible probability. This is because not only does it take time for subsequent processes such as repairs when microballs are mounted at unnecessary positions on the board, but if the microballs remain on the board as they are, they are manufactured through the entire process. This is because the value of the device is lost (becomes defective).

  In a ball mounting apparatus that mounts microballs on a substrate using a mask, the mask and the substrate are overlapped, and microballs are mounted (arranged) on the substrate through a plurality of holes formed in the mask. At this time, an unnecessary ball (stray ball) may be adsorbed on the lower surface (surface on the substrate side) of the mask due to an electric or physical adsorption action. If this mask is superimposed on the next substrate in a state where the stray ball is attracted to the lower surface of the mask, there is a possibility that a minute ball is mounted at an unnecessary position on the substrate. Further, if the flux adheres to the lower surface of the mask, there is a possibility that the ball is attracted or the flux is transferred to an unnecessary position on the wafer, thereby lowering the conductive performance. Therefore, in the ball mounting apparatus, when the ball is mounted on one substrate, the lower surface on the substrate side of the mask is wiped and then the ball is mounted on the next substrate.

  The mask described in Patent Document 1 has convex portions (two-dimensionally formed) extending in two directions orthogonal to each other so as to correspond to a plurality of chips constituting the wafer. For this reason, the part where the convex part intersects becomes a dead space, and even if the lower surface of the mask is wiped, it is difficult to eliminate the possibility that the lost ball remains on the lower surface or the flux remains. That is, when the lower surface of the mask described in Patent Document 1 is wiped, the stray ball may move within a frame-like (lattice-like) region formed by the convex portions, but contacts the edges of the convex portions. At this stage, it is caught in the edge of this convex part and stays in this region.

  One embodiment of the present invention is a ball mounting device, which includes a plurality of holes, a mask for mounting a micro ball on the substrate through the plurality of holes, and the mask overlaid on the substrate. In this state, the ball mounting apparatus has a ball supply unit for supplying microballs on one surface opposite to the substrate side of the mask, and the mask is on the other side on the substrate side. The surface is provided with a plurality of elongated protrusions extending linearly only in the first direction while avoiding the plurality of holes. The ball mounting apparatus further includes a cleaning unit for wiping the other surface of the mask, the cleaning unit moving in a first direction while being in contact with the other surface of the mask while the mask is separated from the substrate. Have

  If the plurality of elongated projections are masks that extend linearly only in the first direction while avoiding the plurality of holes on the other surface on the substrate side, the first plurality of elongated projections extend. By wiping the other surface along the direction, the plurality of elongated protrusions are unlikely to obstruct wiping of the other surface. In other words, the fact that the other surface is provided with a plurality of elongated protrusions that extend linearly only in the first direction while avoiding the plurality of holes means that the other surface is wiped in the direction other than the first direction. It means that there are no protrusions that would impede purification. Therefore, even if a minute ball is attracted to the other surface by static electricity or the like and becomes a lost ball, the lost ball is wiped along the first direction in which the plurality of elongated protrusions extend, thereby Can be removed out of the mask while moving (sliding) in the first direction.

  Further, the plurality of elongated protrusions are provided avoiding the plurality of holes. For this reason, these elongate convex parts do not interfere with the mounting of the minute balls on the substrate. Further, when the substrate and the mask are overlapped, the elongated protrusions formed so as to avoid a plurality of holes serve as the legs of the mask. Therefore, even when a flux is applied to the substrate so as to correspond to a plurality of holes and a fine ball is mounted thereon, the flux is difficult to adhere to the mask when the mask is stacked on the substrate. . Moreover, even if the flux adheres to the lower surface of the mask, the flux is applied to the edges of the elongated projections by wiping the other surface along the first direction in which the plurality of elongated projections extend. It is possible to remove (wipe off) the flux satisfactorily without leaving it.

Therefore, the above apparatus is a mask for mounting microballs at a predetermined position on the substrate, and avoids a plurality of holes provided so as to correspond to the predetermined position on the substrate, and the plurality of holes. A mask having a plurality of elongated protrusions extending linearly only in the first direction is preferable .

  More preferably, the cleaning unit includes a cleaning medium that moves in the first direction while contacting the other surface of the mask. An example of the cleaning medium is a cloth such as a nonwoven fabric. Since the other surface of the mask is only provided with an elongated protrusion extending only in the first direction, the other surface of the mask can be efficiently cleaned by the cleaning unit moving in the first direction, and the simple configuration Thus, a ball mounting device having a high cleaning effect can be provided.

  Examples of the ball mounting device include a device having a stage for supporting a substrate and a stage transfer device for transferring (carrying) the stage. An embodiment in which a mask is arranged so that a first direction in which a plurality of elongated protrusions extend and a substrate transfer direction are orthogonal to each other and the cleaning unit is moved in a direction orthogonal to the substrate transfer direction is an embodiment of the present invention. This is one preferred form of such a ball mounting device.

  Furthermore, in the ball mounting apparatus according to one aspect of the present invention, the ball supply unit includes a head capable of holding a group of minute balls on a part of one surface of the mask, and the head moves along the one surface of the mask. It is preferable to provide a moving means. In addition, the moving area in which a group of microballs is held on one surface of the mask by the head is used to perform control including moving the moving area so that a part of the locus of the moving area overlaps. It is preferable to further have a control unit. The control unit may control the ball supply unit (head and moving means) or may control the entire ball mounting apparatus.

  The mask included in the present invention is provided with an elongated convex portion extending only in the first direction on the other surface, and is one-dimensional or anisotropic having a directionality on the other surface, not isotropic in all directions. Adopts a highly configurable structure. By adopting a highly directional configuration, the other surface of the mask can be efficiently cleaned with a simple configuration by a cleaning method that moves the unit in that direction. In addition, the microball is held in a moving area, which is a virtual area that occupies a part of one surface of the mask, and the moving area has an appropriate area and is wide. Therefore, the load by the microball itself and the pressure or load for holding the microball in the moving area are applied to a range having an appropriate area of a part of the mask, and the range includes a plurality of elongated protrusions. It is isotropic or has a two-dimensional spread. For this reason, the elongated protrusions extending only in the first direction can support the pressure or load applied to the mask to hold the minute ball in the moving area, and the mask is bent by such pressure or load. Can be prevented from occurring. A suitable means capable of forming a moving area that occupies a part of one side of the mask and moving the moving area in any two-dimensional direction is to prevent the microballs from escaping. This is a head capable of holding a group of minute balls on a part of one surface of the head.

  Furthermore, by forming a moving area in which a group of minute balls is held, the density of the minute balls in the moving area can be increased even with a relatively small number of minute balls. For this reason, the microballs can be efficiently filled into the holes of the mask through which the moving area passes, and the total number of microballs supplied on the mask can be reduced. By moving the moving area so that part of its trajectory overlaps, the entire mask or at least the area where the ball is transferred can be covered without omission, so the occurrence rate of minute ball filling mistakes on the substrate is extremely low. Can do.

  One preferred form of head for constructing the moving area includes means for sweeping around the moving area on one side of the mask to collect the microballs into the moving area, eg, a member protruding from the head, or The thing which is equipped with the opening which blows off gas can be mentioned. One form of the member protruding from the head is a so-called squeegee that provides an effect of sweeping one surface of the mask. A squeegee extending in a tangential direction of a circular moving area for collecting minute balls is one of simple straight squeegees.

  By using a member protruding from the head or a head provided with a gas outlet, it is possible to prevent the microball from escaping from the moving area due to the member protruding from the head or the gas blowout, and one of the masks. The area around the moving area of the surface can be pressurized. That is, the member protruding from the head or the gas outlet has a function of pressing the mask around the moving area against the substrate. Then, since the pressure is distributed around the moving area, as described above, it is easy to support the elongated projections extending in only one direction provided on the other surface of the mask. Further, by pressing the mask around the moving area, it is possible to suppress the bending of the mask due to the warp or distortion of the mask in the moving area, and it is possible to suppress the generation of a stray ball.

  Further, as one preferred form of the head, the head can be rotated around an axis perpendicular to the mask, and the rotation of the microballs on a part of one side of the mask prevents the microballs from escaping. A head that can hold a group can be mentioned. For example, by rotating a head provided with a plurality of squeegees, a force can be applied in the direction of the circular moving area to a minute ball around the circular moving area. A form in which a plurality of squeegees are arranged in multiple directions in the direction in which they move by the rotation of the head is one of the preferred forms of the head. According to such a head, even if a minute ball leaks from one squeegee, the minute ball can be caught by another squeegee. As a result, the microballs can be reliably collected in the direction of the circular area.

  When the substrate on which the microballs are mounted is a semiconductor device wafer or workpiece (workpiece), the substrate tends to increase in size, and the mask increases in size accordingly. On the other hand, as device integration progresses, microballs (conductive balls) serving as electrodes tend to be miniaturized. An example of the conductive ball is a solder ball, a gold ball or a copper ball having a diameter of about 30 to 300 μm. The smaller the ball to be mounted, the higher the possibility that the ball gets into a minute gap and becomes a lost ball. Therefore, when the ball is mounted on the substrate, it is important to reduce the influence of the gap generated between the substrate and the mask due to the distortion and warpage of the mask.

  In Patent Document 1, a mask made of a magnetic material is used, and the mask is tightly fixed to the substrate by the magnetic force of a permanent magnet while being positioned with respect to the substrate fixed to the stage. Some semiconductor devices do not like the influence of a magnetic field. For manufacturing such a device, a close contact method in which a substrate is sandwiched between a permanent magnet and a mask and a magnetic force directly acts on the substrate is not appropriate.

  On the other hand, according to the ball mounting apparatus included in the present invention, the periphery of the moving area can be pressed without sandwiching the substrate between the permanent magnet and the mask. Furthermore, instead of improving the flatness (surface accuracy) of the entire mask with a strong suction force, it is possible to partially improve the flatness (surface accuracy) of the moving area, so as to counter the strong suction force. A simple mask structure is not required.

  In the case of using the head as described above, it is preferable that the diameter of the outer periphery of the region protruding from the head or the area pressurized by the gas blowing is larger than the maximum interval among the intervals between the elongated protrusions adjacent to each other. . It is more preferable that the diameter of the outer periphery of the member protruding from the head or the region pressurized by the gas blowing is larger than the maximum interval between the three elongated protrusions arranged in succession. By doing in this way, the force (pressing) applied by the head can be supported by a plurality of elongated protrusions arranged in parallel to each other.

  In this specification, a substrate indicates an object on which a minute ball is mounted, and includes a semiconductor wafer, a circuit board, and other workpieces. These substrates include a substrate that has scribe lines extending in at least two directions intersecting each other and that can be divided into a plurality of workpieces (pieces / chips) along the scribe lines. In this case, it is preferable that the first direction in which the plurality of elongated protrusions included in the mask extend is one of the two directions in which the scribe line extends. That is, the mask preferably includes a plurality of elongated protrusions extending linearly only in one of the two directions in which the scribe line extends. More preferably, the plurality of elongated protrusions may be provided so as to coincide with a scribe line extending in one direction of scribe lines extending in two directions. Such a configuration is one of the preferred forms when arranging the plurality of elongated protrusions on the other surface of the mask so as to extend linearly only in the first direction while avoiding the plurality of holes.

According to still another aspect of the present invention, a plurality of holes for mounting microballs at predetermined positions on the substrate and a plurality of holes on the lower surface of the mask facing the substrate are avoided and straight in only the first direction. In this method, a fine ball is mounted on a substrate through a mask having an elongated protrusion provided in a specific manner. This method for mounting microballs includes the following steps.
(A) The mask and the substrate are overlapped with the lower surface of the mask facing the substrate.
(B) By supplying minute balls onto the mask, the minute balls are arranged (mounted) at predetermined positions on the substrate through a plurality of holes in the mask.
(C) With the mask removed from the substrate, the cleaning medium is moved in the first direction to wipe the lower surface of the mask.

  According to this ball mounting method, after the microballs are mounted on one or several substrates, the mask is removed from the substrate, and the cleaning medium is moved in the first direction, whereby the lower surface of the mask can be efficiently wiped. Therefore, it is possible to reduce the possibility that a lost ball or flux is attached to the mask, and it is possible to suppress the occurrence of defects caused by them.

The step (b) of arranging (mounting) the fine balls preferably includes the following steps.
(B1) A moving area in which a group of minute balls is held is formed on the upper surface of the mask.
(B2) The moving area is moved so that a part of the locus of the moving area overlaps.

  FIG. 1 is a top view showing a schematic configuration of a microball mounter. FIG. 2 is a side view showing a schematic configuration of the microball mounter. In FIG. 1, the holes 111 formed in the mask 110 are omitted. The microball mounter 1 is electrically conductive at a predetermined position on the upper surface of a substrate (workpiece) of about 8 inches (diagonal length or diameter is about 20 cm) or 12 inches (diagonal length or diameter is about 30 cm). This is for mounting (mounting) a small ball B having a characteristic.

  FIG. 3 shows an example of the substrate. As shown in FIG. 3, the substrate 100 is, for example, a planar circular semiconductor wafer of 8 inches or 12 inches. The semiconductor wafer 100 is mounted (mounted) by the microball mounter 1 at a predetermined position 103 on its upper surface 100a with conductive microballs B that function as electrodes. Thereafter, the semiconductor wafer 100 is divided (cut) along a plurality of scribe lines 101x along the X direction and a plurality of scribe lines 101y along the Y direction to form a plurality of semiconductor devices (chips) 102.

  The plurality of scribe lines 101x along the X direction are provided in parallel to each other so as to have a predetermined pitch Px. The plurality of scribe lines 101y along the Y direction are provided in parallel to each other so as to have a predetermined pitch Py. In this example, the formed semiconductor device 102 has a square outer shape, and the pitch Px is equal to the pitch Py. Note that the scribe line is a boundary line for cutting (dividing) the wafer 100 into each semiconductor device 102, and does not necessarily require a clear (visible) line on the wafer 100. It may be a straight line.

  The conductive fine ball B functioning as an electrode has, for example, a solder ball (eg, silver (Ag) or copper (Cu)) having a diameter of 1 mm or less, specifically about 30 to 300 μm in diameter. A ball made of tin (Sn)), a metal ball made of gold or copper, or a conductive ball in which a treatment such as plating is applied to a plastic ball. In this example, a solder ball of about 100 μm is used as the minute ball B.

  The microball mounter 1 of this example includes an XYZθ stage 2 that supports the wafer 100 in a horizontal state by a method such as suction, and a loader / loader that loads (supplys) / unloads (stores) the wafer 100 with respect to the stage 2. An unloader device 3, a pre-alignment device 4 for finely adjusting the position of the stage 2, a warpage correction device 5 for correcting the warpage of the wafer 100, and a flux printing device 6 for applying a flux to the wafer 100, , A ball mounting device 7 for mounting (arranging) the conductive balls B on the wafer 100 via the mask 110, and a stage transfer for transferring the stage 2 between these devices 3, 4, 5, 6 and 7 The apparatus 8 has a stage 2 and a control unit 9 for controlling these apparatuses 3, 4, 5, 6, 7 and 8. Many of the control units 9 are configured using a computer or a microcomputer. The control program (program product) is provided by being recorded on an appropriate recording medium such as a ROM. The microball mounter 1 of this example can be controlled via a computer network such as a LAN, and can also provide a program from a server on the network.

  In this ball mounter 1, a pre-alignment device 4, a loader / unloader device 3, a warp correction device 5, a flux printing device 6, and a ball mounting device 7 are arranged in order along the transfer direction (transport direction) X. Yes. The stage 2 is a platform that supports the wafer 100 and has a disk shape that is substantially the same as or slightly different from the wafer 100, and an upper surface 21 a that serves as a support surface that supports the lower surface 100 b of the wafer 100. And a frame 22 provided around the support 21 (see FIG. 8). The support surface 21a is processed flat. The support base 21 includes a plurality of suction holes 23 on the support surface 21a for supporting the wafer 100 by suction. The support base 21 is configured such that an external vacuum generator (not shown) applies a negative pressure to the vicinity of the support surface 21a through the holes 23 so that the lower surface 100b of the wafer 100 is in close contact with the support surface 21a. By using such a support base 21, the flatness of the upper surface 100a of the wafer 100 can be improved.

  An upper surface (upper end surface) 22a of the frame 22 is located around the support surface 21a of the support base 21 and has a substantially square outer shape. An upper end surface 22 a of the frame 22 is in contact with a ball arrangement (ball transfer, ball arrangement) mask 110 in the ball mounting device 7, and supports the ball arrangement mask 110 in a region outside the wafer 100.

  Although not shown, the stage 2 includes a plurality of actuators that support the support base 21 and move the support base 21 up and down. These actuators are driven by one or a plurality of motors in conjunction or independently. That is, the stage 2 can move the support surface 21a up and down with respect to the upper end surface 22a by driving the actuator as a moving mechanism.

  The flux printing apparatus 6 is a screen printing apparatus, and a material (flux) for bonding the wafer 100 and the conductive ball B to a predetermined position 103 of the upper surface 100a of the wafer 100 where the electrode is formed. It is for applying. The flux printing apparatus 6 includes a unit 61 for cleaning the printing mask. The cleaning unit 61 cleans the printing mask every time printing of the flux on one wafer 100 is completed or when it is determined that the printing mask needs to be cleaned.

  FIG. 4 shows a schematic configuration of the ball mounting device 7 in a top view. FIG. 5 shows a schematic configuration of the ball mounting device 7 in a side view. In FIG. 4, the hole 111 formed in the mask 110 is omitted.

  The ball mounting device 7 includes a ball array mask 110 for mounting the conductive balls B on the upper surface 100a of the wafer 100, a mask holding mechanism 72 (see FIG. 2) for holding the ball array mask 110, A ball supply unit 74 that supplies a plurality of conductive balls B to the upper surface 110 a of the mask 110 and a cleaning unit 140 for cleaning the ball arrangement mask 110 are provided.

  The ball supply unit 74 is for supplying the ball B onto the ball arrangement mask 110 in the ball filling state. That is, the wafer 110 is moved so that the mask 110 set on the mask holding mechanism 72 and the wafer 100 overlap with each other, and the mask 110 is aligned with the wafer 100 by the ball supply unit 74. A ball B is supplied to the top. The supplied balls B are mounted (arranged) at predetermined positions on the wafer 100 through the plurality of holes 111 of the mask 110.

  The ball supply unit 74 includes a head 120 that can rotate around an axis 121 that is perpendicular to the mask 110, and a head moving device 130 that moves the head 120 along the upper surface 110 a of the mask 110. The operations of the head 120 and the head moving device 130 are controlled by the control unit 9 described above.

  The head moving device 130 supports the motor 131 via a motor 131 that supports the head 120 and an arm 132 that can expand and contract in the Y direction so that the head 120 rotates about an axis 121 perpendicular to the mask 110. A carriage 133. The carriage 133 is movable in the X direction along the carriage shaft 134. Therefore, the head 120 can be moved in the XY direction on the mask 110 by the arm 132, the carriage 133, and the carriage shaft 134, and is set at an arbitrary position. In addition, the control unit 9 stores a program 135 for controlling the head moving device. By controlling the operation of the head moving device 130 via the control unit 9 based on the control program 135, the head 120 can be arbitrarily moved along the upper surface 110a of the mask 110 or across the upper surface 110a. It can be moved so as to draw the locus 128 of. In other words, the head 120 is movable in a straight line, a circle, or an ellipse in the XY plane.

  The cleaning unit 140 performs cleaning around the lower surface 110 b of the mask 110 with the wafer 100 detached from the mask 110.

  FIG. 6 shows an example of the ball arrangement mask 110. The ball array mask 110 includes a plurality of holes (openings) 111. The plurality of holes 111 are formed in a size suitable for inserting minute conductive balls B one by one. The plurality of holes 111 formed in the mask 110 correspond to a predetermined position (electrode position) 103 where the conductive ball B of the wafer 100 is mounted.

  The wafer 100 is divided into a plurality of semiconductor devices 102. In the mask 110, the conductive balls B are arranged at predetermined positions 103 of the semiconductor devices 102. Therefore, the plurality of holes 111 are formed with a repetitive design (pattern). These holes 111 are also called openings, openings, pattern holes, and the like. The holes 111 may be collectively referred to as an opening pattern. The mask 110 is fixed to the mask frame 114 and held by the mask holding device 72 in a state where a certain amount of tension is applied.

  The lower surface 100b of the mask 110 is provided with a plurality of elongated protrusions (projections) 112 that extend linearly only in the first direction while avoiding the plurality of holes 111. In this example, these elongated protrusions 112 extend in the Y direction orthogonal to the X direction in which the wafer 100 is transported. The Y direction coincides with the Y direction of the scribe line 101x in the X direction and the scribe line 101y in the Y direction of the wafer 100. Further, the elongated protrusions 112 are disposed at the center in the width direction of the scribe line 101y extending in the Y direction of the wafer 100 when the mask 110 and the wafer 100 are aligned. That is, the elongated protrusions 112 are arranged in parallel to each other at a predetermined pitch P1 equal to the pitch Py of the scribe lines 101y in the Y direction of the wafer 100.

  Each elongated protrusion 112 has a very small width in the X direction with respect to the length in the Y direction, and has an elongated shape as a whole. Further, the elongated protrusions 112 provided on the mask 110 have the same length in the Y direction and the width in the X direction, and are arranged in parallel to each other. The length of the elongated protrusions 112 in the Y direction is slightly longer than the diameter of the wafer 100, and each elongated protrusion 112 protrudes from the upper surface of the wafer 100 when the mask 110 is overlapped with the wafer 100.

  An example of a method for manufacturing these elongated protrusions 112 is a method of thinning other portions while leaving the elongated protrusions 112 by machining or etching a resinous film, a metal thin plate, or the like constituting the mask body 113. It is. In this method, the elongated protrusion 112 can be formed integrally with the mask body 113. Another example of the manufacturing method is to add the elongated protrusions 112 to the mask body 113 made of a resinous film, a metallic thin plate, or the like by using a method such as (photo) resist or plating. This method is a method of forming the elongated protrusion 112 later, that is, a method of increasing the length of the elongated protrusion 112 without changing the thickness of the mask body 113. These elongated protrusions 112 may be made of the same material as the mask body 113 or may be made of another material. It is also possible to form the mask body 113 with a plurality of layers, and the elongated protrusions 112 using one layer may be formed. The elongated protrusion 112 can have a function of suppressing the warpage and distortion of the mask body 113.

An example of the dimensions of the mask 110 when mounting 100 μm conductive balls B on a 12-inch wafer 100 is as follows.
Mask body 113 thickness (film thickness): 65 μm
The height of the elongated protrusion 112 (hereinafter also referred to as a vertical beam): 45 μm
Width of elongated projection 112 (vertical beam): 40 μm
The shortest length of the elongated protrusion 112 (vertical beam): 12 inch diameter of the hole 111: 115 μm
Minimum pitch of adjacent holes 111 (distance between centers of adjacent circular holes 111 (minimum)): 200 μm
Minimum length of the portion between the adjacent holes 111 (the length of the portion where the mask body 113 remains / the shortest distance between the adjacent circular holes 111): 85 μm
The width of the scribe lines Px and Py is 300 μm, and the distance between the vertical beam (bar) 112 and the hole 111 is longer than the shortest distance between the holes 111.

  FIG. 7 shows the configuration of the head 120 as seen through from above. FIG. 8 is a cross-sectional view showing a state in which the conductive ball B is mounted on the wafer 100 by the ball mounting device 7. FIG. 9 shows an example of the locus of the moving area 125. FIG. 10 shows another example of the locus of the moving area 125. In FIG. 7, the holes 111 formed in the mask 110 are omitted for convenience.

  As shown in FIGS. 4, 5, 7, and 8, the head 120 includes a disk-shaped support 122 and six sets of squeegees 123 protruding from the lower surface 122 a of the support 122 toward the upper surface 110 a of the mask 110. And. The center of the support 122 is connected to a shaft 121 that extends in a direction perpendicular to the mask 110. The head 120 is rotationally driven by the motor 131 counterclockwise around the shaft 121 as viewed from above. In the head 120, the motor 131 is means for rotating the support 122 around the shaft 121 along the upper surface 110 a of the mask 110. The shaft 121 is driven by the arm 132, the carriage 133, and the carriage shaft 134. , Moved in any direction along the upper surface 110a of the mask 110 (on the XY plane). Therefore, according to the ball supply unit 74, the head 120 can be moved along the upper surface 110 a of the mask 110 so as to draw an arbitrary locus 128 while rotating the head 120 by the head moving device 130.

  In addition, a ball replenishing device 136 for replenishing the conductive balls B onto the mask 110 via the inside of the shaft 121 is mounted on the carriage 133. The amount of the ball B replenished from the ball replenishing device 136 is controlled by the control unit 9.

  Each of the six sets of squeegees 123 includes a plurality of sweep members 124 attached so as to be rectangular when viewed from above. The sweep member 124 is attached to the support 122 such that the tip of the squeegee 123 that contacts the upper surface 110a of the mask 110 moves backward. The sweep member 124 may be any member that is relatively soft in contact with the upper surface 110a of the mask 110 and can sweep up the conductive balls B riding on the mask 110. Further, it is desirable that the sweep member 124 has elasticity that does not scrape the ball B once inserted into the hole 111 of the mask 110. As a suitable example of the squeegee 123, there can be mentioned a structure in which a sweep member 124 formed by bending both ends of a wire extending in the longitudinal direction along the upper surface 110a of the mask 110 into a U shape is attached to the support 122.

  In the head 120 of the present embodiment, the squeegee 123 is arranged around the inner circle 125 concentric with the rotary shaft 121 at an equal pitch in the circumferential direction and in the counterclockwise direction tangential to the inner circle 125. It is arranged to extend linearly to 126. Therefore, when the squeegee 123 is in contact with the upper surface 110a of the mask 110 and the support 122 is rotated counterclockwise as viewed from above, the conductive ball B in the traveling direction (rotation direction) of the squeegee 123 is as shown in FIG. As shown by an arrow A1, it is pushed away in the direction of the inner circle 125 (in the region of the inner circle 125). For this reason, the conductive balls B remaining on the upper surface 110 a of the mask 110 move in the direction of the inner circle 125 and are collected inside the inner circle 125.

  Therefore, according to the head 120, the conductive balls B on the mask 110 do not dissipate, and the collective balls Bg of the conductive balls B are placed on the inner circle, that is, the moving area 125, which is a part of the upper surface 110 a of the mask 110. The moving area 125 moves on the mask 110 together with the head 120. During the movement of the moving area 125, the rotation of the head 120 sweeps the periphery 127 of the moving area 125 on the upper surface 110a of the mask 110, and the conductive ball B does not dissipate around the periphery 127 of the moving area 125. The outer circle 126 (the region 127 between the inner circle 125 and the outer circle 126 in the outer circle 126) is collected toward the inner circle 125 that is the moving area 125.

  In the drawing, the areas shown as the inner circle 125 and the outer circle 126 are virtual. However, when the head 120 is moved while being rotated by the head moving device 130 on the upper surface 110 a of the mask 110, the excess conductive balls B remaining in the region 127 between the inner circle 125 and the outer circle 126 are removed from the head 120. Are collected in the center direction (inside the inner circle 125).

  A plurality of squeegees 123 arranged around the circular moving area 125 of the head 120 are also suitable for securely pressing the portion 127 around the moving area 125. That is, in the ball supply unit 74 of this example, a region 127 between the inner circle 125 and the outer circle 126 corresponds to a region pressed by the squeegee 123. When the periphery 127 of the moving area 125 is pressed, the flatness (surface accuracy) of the moving area 125 is partially improved. Accordingly, the flatness of the mask 110 is improved in a limited region where the conductive ball B is filled, that is, in the moving area 125, so that it is possible to prevent the occurrence of a stray ball.

  Furthermore, in the ball supply unit 74 of the present example, the diameter of the outer periphery of the region 127 pressed by the squeegee 123, that is, the diameter R1 of the outer circle 126 is the plurality of elongated protrusions of the ball arrangement mask 110 described above. The head 120 is formed so as to be larger than the interval P1 at which 112 is arranged. When the diameter R1 of the outer periphery of the area 127 pressed by the squeegee 123 is larger than the interval P1 between the elongated protrusions 112, at least one elongated protrusion 112 of the plurality of elongated protrusions 112 is always directly under the area 127. The portion 112 is present, and the mask 110 can be prevented from bending. In addition, since the pressurized region 127 has a sufficient area across the plurality of elongated protrusions 112, the head 120 adds to the pressurized region 127 of the mask 110 regardless of the moving direction of the moving area 125. The force can be supported by the plurality of elongated protrusions 112 directly below.

  The squeegee 123 is not limited to the one using a U-shaped wire. In addition to this, as the squeegee 123, a rubber plate shaped so as to be in contact with the upper surface 110a of the mask 110, an elastic member such as a sponge, a conductive sponge, and a polyimide thin plate are laminated in a U shape to be laminated. Examples thereof include those in which a fine wire made of resin or metal is linearly attached to the support 122 like brush hair. Still another example of the squeegee 123 includes a square support and two sets of squeegees having a V shape in plan view extending from the back surface of the support toward the upper surface 110a of the mask 110. Mention may be made of the rectangular moving area 125 formed between the squeegees of the set. The head 120 having such a squeegee can hold the conductive ball B in the moving area 125 by vibrating. In either case, the number of squeegee sets is arbitrary.

  A head equipped with these squeegees is suitable for surely collecting the balls B while flexibly contacting the upper surface 110a of the mask 110 (mask main body 113). Further, the load from the head is not concentrated on the spot or line and applied to the mask, and the mask 110 (mask body 113) supported by the elongated protrusion 112 formed only in one direction is prevented from being bent. it can.

  FIG. 9 shows an example of a trajectory 128 for moving the circular moving area 125 so as to cover an area corresponding to at least the circular wafer 100 on the upper surface 110a of the mask 110. In FIG. 9, the holes 111 formed in the mask 110 are omitted.

  In order to fill the plurality of holes 111 of the mask 110 with the conductive balls B by moving the head 120, the circular moving area 125 is traced on the upper surface 110 a of the mask 110 along a spiral or spiral locus 128. It is good to move. The spiral or spiral locus 128 is suitable when the wafer 100 is circular, the mask 110 is circular, or the entire region filled with the conductive balls B is circular.

  Further, while rotating the head 120, the head 120 is moved from the outside of the region where the hole 111 is provided to the vicinity of the center of the mask 110, and then spirally formed from the central portion O of the mask 110 toward the peripheral portion. By moving to (in a spiral locus 128), unfilling of the conductive balls B in the central portion O of the mask 110 and in the vicinity thereof can be reduced.

  In FIG. 9, the locus 128 of movement of the moving area 125 is represented by a line on which the rotation center of the head 120 moves. For the sake of simplicity, the head 120 and the moving area 125 are both shown as the same circle. However, as described above, the moving area 125 is formed concentrically with the head 120 and has the same size. It will not be. However, since the moving area 125 is concentric with the head 120, the central trajectories 128 as they move substantially coincide.

  In order to cover the entire area of the upper surface 110 a of the mask 110 corresponding to at least the circular wafer 100 with the moving area 125 without omission, the head 120 is moved by the head moving device 130 so that one of the trajectories 128 of the moving area 125 is set. The parts are preferably moved so that they overlap. For example, when the diameter of the moving area 125 is 40 mm, the spiral pitch is preferably about 8 mm. Under this condition, the overlap rate (the rate at which the next track 128 overlaps one track 128) is about 80%.

  As the trajectory 128, it is possible to select a trajectory in which adjacent portions overlap each other by approximately 50%. By moving the head 120 along such a trajectory (a trajectory having an overlap rate of approximately 50%) 128, the moving area 125 results in the region corresponding to at least the circular wafer 100 in the upper surface 110a of the mask 110. Move so that it passes almost twice. Thereby, the conductive balls B are filled in the plurality of holes 111 of the mask 110.

  In order to suppress filling leakage of the conductive balls B into the opening pattern of the mask 110, it is desirable to move the moving area 125 so as to draw a trajectory 128 having a high overlapping rate. On the other hand, when the overlapping rate of the trajectory 128 of the moving area 125 is high, the processing time required to arrange the conductive balls B on the entire wafer 100 becomes long. Further, when the overlapping rate of the trajectory 128 of the moving area 125 is high, the consumption amount of the conductive ball B per unit time is reduced, and the ball B exists in the moving area 125 for a long time. The probability that the ball B is damaged increases. Therefore, the moving area 125 is preferably moved so as to draw a trajectory 128 with an overlap rate in the range of 10% to 98%. More preferably, the moving area 125 is moved to draw a trajectory 128 with an overlap rate ranging from 30% to 95%. A trajectory 128 having an overlap rate of 40% to 90% is an optimal trajectory when the moving area 125 is moved.

  As shown in FIG. 8, when the moving area 125 is moved while rotating the squeegee 123, the group Bg of the conductive balls B is unevenly distributed in a crescent shape on the rear side in the traveling direction. Distributed. That is, inside the moving area 125, there are a crescent-shaped region 125a where the conductive ball B exists and a region 125b where the conductive ball B does not exist. Furthermore, a portion 125c where the conductive ball B is formed in one layer is formed at a boundary portion between the region 125a where the conductive ball B exists and the region 125b where the conductive ball B does not exist. In the portion 125 c, the conductive ball B falls into the hole 111 of the mask 110 due to its own weight, and the hole 111 of the mask 110 is easily filled with the conductive ball B.

  The operation (rotation and movement) of the head 120 may be determined in view of the following conditions. If the moving speed of the head 120 is too slow, the time required to dispose the conductive balls B over the entire wafer 100 becomes long. On the other hand, if the moving speed of the head 120 is too high, the probability that the moving area 125 will pass before the conductive ball B falls into the hole 111 of the mask 110 increases. Therefore, the moving speed of the head 120 is preferably in the range of 2 to 60 mm / s. The moving speed of the head 120 is more preferably in the range of 5 to 40 mm / s.

  Furthermore, if the rotation speed of the head 120 is too low, the movement of the conductive ball B inside the moving area 125 becomes insufficient, and the area of the region 125c where the conductive ball B exists in a single layer may be reduced. . In this case, the occurrence rate of the filling mistake of the ball B increases. Therefore, the rotation speed of the head 120 is preferably 10 rpm or more. On the other hand, if the rotational speed is too high, the moving speed of the ball B increases, and the probability that the conductive ball B passes through without falling into the hole 111 of the mask 110 increases. Also in this case, the incidence of miss filling of balls B increases. Therefore, the rotation speed of the head 120 is preferably 120 rpm or less. A more preferable range of the rotation speed of the head 120 is 30 to 90 rpm.

  In the ball mounting apparatus 7 of the present example, a head 120 having a moving area 125 having a diameter of 40 mm is used. The head 120 is rotated at a rotation speed of 45 rpm, and the locus 128 of the moving area 125 is 40% to 90%. The program is controlled so as to move at a moving speed of 20 mm / s so as to overlap with each other.

  Note that the appropriate area of the moving area 125 varies depending on conditions such as the diameter of the conductive ball B and the size and density of the plurality of holes 111 formed in the mask 110. If the diameter of the conductive ball B is about 10 to 500 μm, it is desirable to use a head 120 that can form a circular moving area 125 having a diameter of 10 to 100 mm on the mask 110. A more preferable range of the circular moving area 125 is 20 to 60 mm.

  FIG. 10 shows different examples of the trajectory 128 of the circular moving area 125. In FIG. 10, the holes 111 formed in the mask 110 are omitted. In this example, the head 120 is moved so that the moving area 125 draws a zigzag, sine curve, or meandering locus 128. Then, the entire area corresponding to at least the circular wafer 100 in the upper surface 110a of the mask 110 is covered by a moving area 125 that draws a zigzag, sine curve, or meandering locus 128. Such a moving method is a combination of a movement of reciprocating the moving area 125 and a movement of moving the moving area 125 in a direction orthogonal thereto. An example of a direction in which the moving area 125 is reciprocated is a direction (X direction) orthogonal to a direction (Y direction) in which the elongated protrusion 112 extends. The moving area 125 may be reciprocated in a direction that obliquely intersects the Y direction in which the elongated protrusions 112 extend, or in the Y direction.

  FIG. 11 shows a schematic configuration of the cleaning unit 140 in a sectional view. FIG. 12 shows the cleaning unit 140 cut along line XII-XII in FIG. The mask 110 is repeatedly stacked on the plurality of wafers 100 one after another, and is used for arranging the conductive balls B on the plurality of wafers 100. Therefore, it is not preferable that the conductive ball B is adsorbed on the lower surface 110b of the mask 110 due to static electricity or the like or the flux adheres to the lower surface 110b of the mask 110 when it is overlapped with the next wafer 100. The cleaning unit 140 wipes the lower surface 110b of the ball arrangement mask 110 by changing the relative position of the ball arrangement mask 110 with the ball arrangement mask 110 removed from the wafer 100. The cleaning unit 140 moves in the Y direction in which the plurality of elongated protrusions 112 linearly extend as indicated by an arrow A2 in FIGS. 1 and 11, and removes a stray ball adsorbed by static electricity or the like outside the mask 110. Or the flux is removed.

  The cleaning unit 140 includes a cleaning medium 141 that wipes in contact with the lower surface 110 b of the mask 110. As the cleaning medium 141, a cloth or the like can be used. The cleaning unit 140 further includes four rollers 142 to 145. One end of the cross 141 is wound around the feeding roller 142, and the other end is wound around the winding roller 143. A direction changing roller 144 is provided between the feeding roller 142 and the take-up roller 143. A contact roller 145 for bringing the cloth 141 into contact with the lower surface 110 b of the mask 110 is provided between the direction changing roller 144 and the take-up roller 143.

  Accordingly, the cross 141 is fed by the feed roller 142 along the Y direction in the direction indicated by the arrow A3 in FIG. 11 (from the right side to the left side in FIG. 11), and the direction is changed by the direction changing roller 144, along the Y direction. 11 moves in the direction indicated by the arrow A4 in FIG. 11 (from the left side to the right side in FIG. 11), and is taken up by the take-up roller 143. The cloth 141 is in contact with the lower surface 110b of the mask 110 by the contact roller 145 from the time when the direction is changed by the direction changing roller 144 to the time when it is taken up by the take-up roller 143, and the lower surface 110b is wiped off. Purify.

  Further, the cleaning unit may be configured such that an unused cloth is wound around the roller 143 and the used cloth is wound around the roller 142. The contact roller 145 may be an elastic body such as sponge or rubber that does not rotate. The shape of the elastic body is not limited to a cylinder, and the portion in contact with the mask via the cloth 141 may be oval or plate-shaped. On the other hand, an organic solvent is applied to the cloth before cleaning the mask. The cloth cleans the mask while wet with an organic solvent. With this organic solvent, the cloth cleaning ability is remarkably enhanced.

  In the cleaning unit 140, both the cleaning unit 140 itself and the cloth 141 slide in the Y direction. Since the elongated protrusion 112 extends only in the Y direction, the cleaning unit 140 moves along the elongated protrusion 112 when the cleaning unit 140 is moved in the Y direction. As described above, when the direction in which the elongated protrusion 112 extends and the movement direction of the cleaning unit 140 coincide with each other, no movement of the contact roller 145 crossing or overcoming the elongated protrusion 112 occurs. Therefore, the cloth 141 is less likely to leave the lower surface 110b of the mask 110 during cleaning, and wiping residue hardly occurs on the lower surface 110b of the mask 110.

  FIG. 13 shows a flowchart for explaining an example of the mounting method of the ball B. When the stage 2 moves to the ball mounting device 7, the position of the support base 21 is finely adjusted in step 201. The wafer 100 supported by the stage 2 and the ball arrangement mask 110 held by the mask holding mechanism 72 are aligned, and the wafer 100 and the mask 110 are set. That is, the mask 110 and the wafer 100 are overlapped with the lower surface 110 b of the mask 110 facing the upper surface 100 a side of the wafer 100.

  In step 202, a moving area 125 in which a group Bg of conductive balls B is held is formed on the mask 110 by the head 120. The head 120 is moved by the head moving device 130 so that a part of the locus 128 of the moving area 125 overlaps. Thereby, the group Bg of the conductive balls B on the mask 110 moves while being pushed (sweeped) by the squeegee 123 (the sweep member 124). Along the trajectory 128 of the head 120 (the moving area 125), the conductive balls B are filled (transferred) into the holes 111 of the mask 110 and arranged at predetermined positions 103 on the wafer 100. The conductive balls B filled in the holes 111 of the mask 110 are in close contact with the flux and are temporarily fixed at predetermined positions 103 of the wafer 100. Thereafter, the wafer 100 on which the conductive balls B are arranged is fixed (mounted) at a predetermined position 103 through a known reflow process.

  When the filling of the conductive balls B into the wafer 100 is completed, in step 203, the wafer 100 is lowered and the ball arrangement mask 110 is removed from the wafer 100. In step 204, the lower surface 110 b of the mask 110 is cleaned by moving the cleaning unit 140 in the direction of the elongated protrusion 112. It should be noted that the cleaning may be controlled not to be performed every time transfer is completed for one wafer 100 but to be performed when it is determined that cleaning is necessary. The cleaning unit 140 and the cloth 141 each wipe the lower surface 110b of the mask 110 while moving in the Y direction. Thereby, even if a stray ball or flux adheres to the lower surface 110b of the mask 110, these are eliminated. Thus, the mounting of the conductive ball B on the upper surface 100a of the wafer 100 is completed.

  As described above, the ball mounting apparatus 7 includes the mask 110 including the plurality of elongated protrusions 112 extending linearly only in the Y direction while avoiding the plurality of holes 111 on the lower surface 110b on the wafer 100 side. . Even if the conductive ball B is attracted to the lower surface 110b due to static electricity or the like to form a lost ball, such a mask 110 can be obtained by wiping the lower surface 110b along the Y direction in which the plurality of elongated protrusions 112 extend. A lost ball can be removed from the mask 110.

  In addition, the ball mounting device 7 includes a head 120 capable of forming a moving area 125 in which a group Bg of conductive balls B is held on the upper surface 110a of the mask 110. Then, the moving area 125 is moved by the head moving device 130 so that a part of the locus 128 overlaps. By using the ball supply unit 74 including the head 120 and the head moving device 130, the density of the conductive balls B in the moving area 125 can be increased even with a relatively small number of the conductive balls B. Can do. Therefore, the conductive ball can be efficiently filled into the hole 111 of the mask 110 corresponding to the portion through which the moving area 125 passes.

  In addition, by using such a ball supply unit 74, the wafer may be sandwiched between the permanent magnet and the mask, and the ball array mask may not be tightly fixed to the wafer by the magnetic force. Flatness can be ensured by pressing only the region of the mask into which the conductive ball B is transferred with the head. For this reason, the ball arrangement mask need not have such a high rigidity that prevents the deflection against the pressure for bringing the entire surface into close contact with the wafer. The mask may be any mask that can support a relatively small number of conductive balls existing in a limited area. Therefore, the group Bg of the conductive balls B collected in the moving area 125 can be supported by the mask 110 having the plurality of elongated protrusions 112 extending linearly only in the Y direction while avoiding the plurality of holes 111 on the lower surface 110b. .

  Further, the flatness of the mask 110 is improved in the moving area 125 by the squeegee 123 protruding from the support 122, so that it is possible to prevent the occurrence of a lost ball. Further, since the diameter R1 of the outer periphery of the region 127 pressed by the squeegee 123 protruding from the head 120 is larger than the interval P1 of the elongated protrusions 112, the plurality of elongated protrusions 112 can support the load due to the squeegee, and the mask Can be prevented from being bent or distorted.

  The back surface 110b of the mask has a highly directional structure in which a plurality of elongated protrusions 112 extend in one direction. Therefore, by moving the cleaning unit 140 along that direction, the lower surface 110b of the mask 110 can be swept or wiped to remove the ball B or flux without clogging.

  In this example, the rotation direction of the head 120 (the rotation direction of the head 120) is a counterclockwise direction when viewed from above, but the rotation direction of the head 120 is a clockwise direction when viewed from above. There may be. When the rotation direction of the head 120 is a clockwise direction when viewed from above, the squeegee 123 and the sweep member 124 are preferably provided in the head 120 as a mirror image reversed arrangement with respect to the arrangement of the present embodiment. Further, in the present embodiment, when the locus 128 of the moving area 125 is spiral, the direction of the locus 128 is clockwise as viewed from above, but the direction of the spiral locus 128 of the moving area 125 is May be counterclockwise as viewed from above.

  Further, the substrate on which the balls are arranged is not limited to the circular substrate (semiconductor wafer) 100 but may be a rectangular electronic circuit substrate (multilayer substrate). Moreover, the mask may be a mask having a filling region that is rectangular as a whole. An example of a multilayer substrate is shown in FIGS. 17 and 18 show an example of a mask for arranging the conductive balls B on this multilayer substrate. FIG. 19 shows an example of the relationship between the area pressed by the head and the plurality of elongated protrusions provided on the mask, and the locus of the area formed by the head when the conductive ball B is mounted on the multilayer substrate. Is shown.

  A resist layer 153 is formed on the upper surface 150a of the multilayer substrate 150 (the upper surface of the substrate body portion 157). The resist layer 153 is removed by etching or the like in the portion where the conductive ball B on the upper surface 150a of the multilayer substrate 150 is mounted. The mask 160 can be set on the substrate 150 by overlapping the substrate 150 and the mask 160 so that the resist layer 153 of the substrate and the plurality of elongated protrusions 162 formed on the mask 160 are in close contact with each other. . Then, by filling the plurality of holes 161 of the mask 160 with the conductive balls B, the conductive balls B are arranged in electrical contact with the electrode positions 156 on the upper surface 150a of the substrate 150, and thereafter Each conductive ball B functions as a connection terminal by being fixed by a process such as reflow.

  For example, 4 × 2 sets (total of 8) of IC chips 154 are mounted on the lower surface of the multilayer substrate 150 (the lower surface of the substrate body portion 157) 150b. These chips 154 are molded, for example, in units of four with a resinous protective layer 155. The multilayer substrate 150 is cut along a plurality of scribe lines 151x and 151y along the X direction and the Y direction to form a plurality (eight) semiconductor devices 152.

  In this substrate 150, the IC chips 154 are mounted at predetermined intervals in units of four, with a predetermined interval in the Y direction, and the IC chips 154 are mounted again at predetermined intervals in units of four. Accordingly, the interval Px between the scribe lines 151x along the X direction is constant, but the interval Py between the scribe lines 151y along the Y direction is not constant. As shown in FIG. 17, the mask 160 for arranging the conductive balls B on the substrate 150 has a spacing Py between the scribe lines 151y in the Y direction so as to coincide with the scribe lines 151y along the Y direction. What provided the some elongate convex part 162 along was preferable. In FIG. 17 and FIG. 18, reference numeral 163 denotes a mask body, and reference numeral 164 denotes a mask frame.

  As shown in FIG. 19, the head 120 has a plurality of elongated protrusions 162 arranged on the lower surface 160 b of the mask 160 such that the outer diameter of the region 127 pressed by the squeegee 123 protruding from the head 120 is aligned. It is preferable to be larger than the maximum interval (the maximum interval of the intervals P2 and P3 between the elongated protrusions 162 adjacent to each other) P3. In this example, the diameter of the outer periphery of the region 127 pressed by the squeegee 123 is larger than the maximum interval (the maximum interval of the intervals between the elongated projections 112 adjacent to each other) P3 in which the plurality of elongated projections 162 are arranged. Is also big. By moving the head 120, a zigzag, sine curve, or meandering trajectory including a reciprocating motion in the X direction so that the moving area 125 is orthogonal to the plurality of elongated protrusions 162 formed along the Y direction. It moves so that 128 may be drawn. By moving the moving area 125 so as to cover at least a region corresponding to the multilayer substrate 150 on the upper surface 160a of the mask 160, the conductive balls B can be arranged in a predetermined range. Also in this case, it is preferable to move the moving area 125 so that the overlapping rate of the trajectory 128 is in the range of 10% to 98%. Note that a spiral trajectory 128 that draws a route along the outer periphery of the square is one of the trajectories suitable for covering the rectangular filling region.

  In the ball mounting apparatus 7 described above, the rotary head 120 is used. However, the head does not necessarily need to rotate. Further, in the above-described ball mounting apparatus 7, the type of head 120 having the sweep member 124 is used to sweep the periphery 127 of the moving area 125 on the upper surface 110 a of the mask 110 and collect the ball B in the moving area 125. However, the head is not limited to this. As the head, a head that blows out a gas such as air and collects the ball B in the moving area 125 may be used. In this case, the head may rotate or may not rotate.

  FIG. 20 shows a configuration of a different head 170. The head 170 includes an air nozzle 171 that blows a gas for sweeping the ball B onto the upper surface 160 a of the mask 160. This head 170 can also be used for the ball supply unit 74 of the ball mounting device 7 in place of the head 120 described above. The air nozzle 171 is attached to the support 122. An example of the air nozzle 171 includes a linear nozzle end 171 a extending to the outer circle 126 in the tangential direction of the inner circle 125 of the back surface 122 a of the support 122. A filter 173 made of sintered metal or the like is attached to the nozzle end 171 a, and air is jetted obliquely downward toward the upper surface 160 a of the mask 160 through the filter 173. The air discharge part 171a of the air nozzle 171 may be configured by a collection of slits and minute cylindrical holes instead of the filter 173. Since the blown air flows on the upper surface 160a of the mask 160 in the direction of the inner circle 125, the head 120 is moved while the conductive balls B are blown off in the direction of the moving area 125 of the inner circle 125 by the air. Can do. Further, the pressure 127 of the air blown onto the upper surface 160a of the mask 160 can suppress the periphery 127 of the moving area 125 filled with the ball B, thereby correcting the distortion and warping of the mask 160.

  FIG. 21 shows a different example of a head 180 that blows out air. The head 180 includes a support 122 and a squeegee type nozzle 181 protruding from the back surface 122a of the head 180 toward the upper surface 160a of the mask 160. The nozzle 181 is formed of an elastic member such as rubber, and presses the mask 160 in contact with the upper surface 160 a of the mask 160. The nozzle 181 includes a blowout port 181a facing inward, and collects the conductive balls B in the moving area 125 by discharging air toward the inside. The head 180 can also be used by being attached to the ball mounting device 7 (ball supply unit 74) in place of the head 120 described above. Further, since the conductive ball B can be moved by the blown air, the conductive ball B can be collected without rotating the head 120.

  In the heads 170 and 180 that blow out a gas such as air, the ball B can be driven by the pressure of the air. Therefore, the ball mounting device 7 can collect the balls B in the moving area 125 without moving the heads 170 and 180 by simply moving the heads 170 and 180 in any direction by the head moving device 130. . Of course, it is also possible to collect the balls B in the moving area 125 by rotating the heads 170 and 180. Since the ball mounting device 7 using the heads 170 and 180 of the type that blows out the gas can omit the motor that rotationally drives the heads 170 and 180, the configuration of the head moving device 130 can be simplified. It is also effective to use an inert gas such as nitrogen gas or argon gas or an ionized gas for controlling the charging property of the conductive ball B instead of air.

  In the present invention, the shape of the moving area 125 where the conductive balls B are collected is such that the head 120 rotates or vibrates (oscillates), and the head 120 travels in an arbitrary direction. It does not become a geometric figure with However, in the ball supply unit 74 that collects the balls B while rotating the head 120, the moving area 125 can be said to be substantially circular. Another example of the ball supply unit 74 is a type that collects the balls B while vibrating the head 120. In such a ball supply unit 74, the moving area 125 is a circle depending on the shape of the squeegee 123 or a polygon circumscribing the circle. Here, the polygon is not limited to a square, but includes a triangle, and more than a pentagon.

  In this example, the ball mounting device is provided as a part of a ball mounter including a loader / unloader device, a warp correction device, and a flux printing device. However, the ball mounting device can be provided alone. is there. In this example, it is desirable that the cleaning unit moves in the Y direction because of the arrangement of the ball mounter. For this reason, the mask is provided with elongated protrusions (vertical bars) extending only in the Y direction. The direction in which the portion is formed can be arbitrarily selected in relation to the moving direction of the cleaning unit. In addition, the elongated protrusions arranged so as to coincide with the scribe lines are examples in which the space between the semiconductor chips can be effectively used as the elongated protrusions. The elongated protrusions do not necessarily have to coincide with the scribe lines, may be arranged in parallel, or may be arranged so that one or more scribe lines are skipped. Further, if a suitable space can be secured in the electrode range of the semiconductor chip, an elongated convex portion may be arranged inside the scribe line.

The top view which shows an example of a microball mounter. The side view which shows the microball mounter of FIG. The top view which shows an example of a board | substrate. The top view which shows schematic structure of a ball mounting apparatus. The side view which shows schematic structure of a ball mounting apparatus. FIG. 4 is a top view showing an example of a mask suitable for mounting microballs on the top surface of the substrate of FIG. 3. The figure which shows an example of a head through the watermark. Sectional drawing which shows the state which mounts the micro ball | bowl on the board | substrate with a ball | bowl mounting apparatus. The figure which shows an example of the locus | trajectory of the area comprised by the head at the time of mounting a ball | bowl on the board | substrate of FIG. The figure which shows the other example of the locus | trajectory of the area comprised by the head at the time of mounting a ball | bowl on the board | substrate of FIG. Sectional drawing which shows schematic structure of a cleaning unit. Sectional drawing cut | disconnected and shown along the XII-XII line | wire in FIG. The flowchart for demonstrating an example of the mounting method of a ball | bowl. The top view which shows the other example of a board | substrate. The bottom view which shows the board | substrate of FIG. Sectional drawing cut | disconnected and shown along the XVI-XVI line in FIG. The top view which shows an example of a suitable mask when mounting a microball on the upper surface of the board | substrate of FIG. Sectional drawing cut | disconnected and shown along the XVIII-XVIII line in FIG. The figure which shows an example of the locus | trajectory of the area comprised by the head at the time of mounting a ball | bowl on the board | substrate of FIG. Sectional drawing which shows a part of other example of a head. Sectional drawing which shows a part of other example of a head.

Explanation of symbols

7 ball mounting device, 74 ball supply unit 100, 150 substrate,
101x, 101y, 151x, 151y Scribe line 102, 152 Semiconductor device (workpiece, piece, chip)
110, 160 Mask 110a, 160a Upper surface of mask (one surface)
110b, 160b The lower surface of the mask (the other surface)
111, 161 hole, 112, 162 Elongated convex portion 120, 170, 180 Head 121 shaft (shaft), 123 squeegee 125 moving area, 128 locus 130 head moving device (moving means), 140 cleaning unit B conductive ball (solder ball) , Micro ball)

Claims (6)

A plurality of holes, and a mask for mounting microballs on the substrate through the plurality of holes;
In a state where this mask is overlaid on the substrate, a ball supply unit for supplying microballs on one surface opposite to the substrate side of the mask;
A ball mounting device comprising:
The mask includes a plurality of elongated protrusions that extend linearly only in the first direction avoiding the plurality of holes on the other surface on the substrate side,
Further, a cleaning unit for wiping the other surface of the mask, the cleaning unit moving in the first direction while contacting the other surface of the mask with the mask being separated from the substrate A ball mounting device. The ball supply unit according to claim 1, wherein the ball supply unit holds a group of minute balls on a part of one surface of the mask;
Moving means for moving the head along one surface of the mask,
Further, the control includes moving the moving area in which a group of microballs is held on one surface of the mask by the head so that a part of the locus of the moving area overlaps by the moving means. A ball mounting device having a control unit for performing 3. The head according to claim 2, wherein the head includes a member protruding from the head or a gas blowing port in order to sweep the periphery of the moving area on one surface of the mask and collect the microballs in the moving area. And
The ball mounting apparatus, wherein a member protruding from the head or a diameter of an outer periphery of a region pressurized by blowing a gas is larger than a maximum interval among adjacent elongated protrusions. In Claim 1, the substrate has a scribe line extending in at least two directions intersecting each other, and can be divided into a plurality of pieces along the scribe line,
The first direction in which the plurality of elongated protrusions extend is one of two directions in which the scribe line extends,
The ball mounting device, wherein the plurality of elongated protrusions are arranged so as to coincide with the scribe line extending in the one direction. A plurality of holes for mounting microballs at a predetermined position of the substrate, and an elongated protrusion provided on a lower surface facing the substrate, avoiding the plurality of holes, linearly only in the first direction; A method of mounting microballs on the substrate through a mask having
Stacking the mask and the substrate with the lower surface of the mask facing the substrate;
By supplying the microballs on the mask, mounting the microballs at a predetermined position of the substrate through the plurality of holes of the mask;
A microball mounting method comprising: wiping the lower surface of the mask with the mask removed from the substrate by moving a cleaning medium in the first direction.   6. The step of mounting the microballs according to claim 5, wherein the step of mounting the microballs includes forming a moving area in which a group of microballs is held on the upper surface of the mask and overlapping a part of the locus of the moving area. A method of mounting a microball, including moving a moving area.

Images