JP2007288209A - Equipment and method for mounting conductive ball - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the equipment and method for mounting conductive balls which can prevent faulty connection of a connecting bump in the manufacturing of the connecting bump formed on a semiconductor element or the like, thereby supplying highly reliable electronic components to the market. <P>SOLUTION: The mounting equipment has a work where pad electrodes are arranged in the predetermined pattern, a table for mounting the work with the pad electrode arrangement side oriented upward, and a mask where a positioning open area is formed which allows conductive balls to be inserted corresponding to the pad electrode arrangement pattern. The mounting equipment mounts the conductive balls onto the pad electrodes through the positioning open area by facing the mask with the pad electrode arrangement side and aligning the positioning open area to the pad electrodes. The table is provided with a vacuum adsorption means for sucking in the aligned mask to bring it into close contact with the pad electrode arrangement side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a conductive ball mounting apparatus and mounting method, and more particularly to an FC (Flip Chip) type semiconductor element, a BGA (Ball Grid Array) or CSP (Chip Scale Package) type electronic component package, and to them. The present invention relates to a mounting apparatus and mounting method suitable for mounting conductive balls when manufacturing connection bumps for area array type semiconductor elements, wiring boards, and electronic component packages, such as corresponding wiring boards.

  In recent years, as mobile terminal devices and notebook personal computers have become faster, more functional, lighter, smaller, and thinner, semiconductor devices constituting electronic components incorporated therein and packages of the semiconductor devices have been developed. However, conflicting characteristics such as downsizing, thinning, and multi-terminal are required. In order to meet this requirement, as shown in FIG. 5 (a) in an enlarged front view and in FIG. 5 (b) in a plan view, a small CSP type or BGA (FBGA type is also available with connection bumps arranged at a narrow pitch. Package) type 4 has been proposed. In this package 4, for example, connection bumps 83 b (83) connected to an external device such as a mother board project on one surface (lower surface) in an area array shape, and connection bumps 83 b (83) connected to the semiconductor element 7. Has a wiring substrate 8 projecting on the other surface (upper surface) in an area array form, and the semiconductor element 7 is flip-chip bonded to the upper surface of the wiring substrate 8 to form the electronic component 5.

  As shown in FIG. 5A, the wiring substrate 8 includes a thin base 81, a pad electrode 82a (82) in which the connection bump 83a projects from the upper surface of the base 81, and the lower surface. The connection bump 83b has a pad electrode 82b (82) protruding therefrom. A conductor pattern is formed on the surface and inside of the base 81 for rewiring. As the substrate 81, a known resin or ceramic substrate, or a substrate on which they are laminated is selected as necessary.

  As a method for manufacturing the electronic component 5, the semiconductor element 7 is mounted on the wiring board 8 provided with the connection bump 83, and the FC is formed by providing the connection bump 83 on the pad electrode 72 of the semiconductor element 7 to form the wiring board 7. May be implemented in In the following description, the semiconductor element 7 and the wiring board 8 are collectively referred to as a work 7 (8).

  As a method of forming the connection bump 83, for example, a printing method in which a paste containing a solder component is printed on the pad electrode 72 (82), and conductive balls (solder balls, copper balls, etc.) are mounted on the pad electrode 72 (82). There are a conductive ball method, a filming method for plating or vapor-depositing a conductor on the pad electrode 72 (82), etc., but the connection bumps 83 can be accurately arranged as compared with a printing method and a filming method, A CSP or BGA type package that can easily obtain the connection bumps 83 having a large volume and little variation, and that requires a highly productive conductive ball system to accurately arrange the small connection bumps 83 at a narrow pitch. 4 has become mainstream.

  According to the conductive ball method, the connection bump 83 is at least electrically conductive to the pad electrode 72 (82) on which the solder paste or flux is printed and the solder paste or flux is printed on the pad electrode 72 (82). It is manufactured through a mounting process of mounting a ball and a reflow process of heating, melting, and fixing the conductive ball to the pad electrode 72 (82).

  As an example of a method of mounting the conductive ball on the pad electrode 72 (82) in the mounting step, the conductive ball is sucked by a suction head using a negative pressure as described in Patent Document 1 below, and the pad electrode There is a so-called adsorption system that is transported to and mounted on 72 (82). However, according to the suction method, there is a problem that the conductive ball is deformed by the suction force of the suction head, but the conductive ball is not mounted on the pad electrode 72 (82) because the separation between the suction head and the conductive ball is poor. There was a problem that mounting failure occurred. Further, the conductive ball is charged by the air flow at the time of adsorption and has an electromagnetic force, and due to the electromagnetic force, an assembly of the conductive balls in a dumped state is mounted on the pad electrode 72 (82), or There is a problem that surplus balls (so-called extra balls) adhere to the surface of the work 7 (8) other than the pad electrode 72 (82), and this problem is particularly noticeable as the diameter of the conductive ball is reduced.

  As a method for solving such a problem of the suction method, a mask having a positioning opening corresponding to the arrangement pattern of the pad electrode 72 (82) is used, and a conductive ball is transferred into the positioning opening by using a conductive ball. There is a so-called transfer method which is mounted on the pad electrode 72 (82).

  An example of a method of mounting a conductive ball on the pad electrode 72 (82) by a transfer method is disclosed in Patent Document 2 below. In the mounting method described in Patent Document 2 below, a flux is applied to the pad electrode 72 (82), the pad electrode 72 (82) and the positioning opening are aligned in the plane direction, and a mask is formed on the wiring board 8. Place the conductive ball on the mask, move the conductive ball with a blade (squeegee), swing the conductive ball into the positioning opening, and mount the conductive ball on the pad electrode 72 (82) To do.

  According to such a transfer method, the above-described problem of the adsorption method can be solved. That is, in the transfer method, since no excessive force is applied to the conductive ball, the deformation of the conductive ball can be prevented, and the mounting of the conductive ball is performed by the action of gravity, so the problem of mounting failure due to the suction can be solved. . Further, even when the conductive ball is charged by the transfer, the assembly of the conductive balls in a dumped state due to the restriction of the size of the positioning opening is not mounted on the pad electrode 72 (82). Since the surface of the work 7 (8) other than (82) is shielded by a mask, the surplus balls do not adhere.

JP 2001-223234 A Japanese Patent Laid-Open No. 10-126046

  However, the mounting of conductive balls by the conventional transfer method exemplified in Patent Document 2 has the following problems. That is, as shown in FIG. 6A, inevitable warpage in the thickness direction due to the difference in expansion coefficient between the pad electrode 72 (82) and the conductor pattern and the work 7 (8), the manufacturing conditions, or the like. The workpiece 7 (8) has a deformation such as a thickness variation. When the mask 92 is placed on the work 7 (8) having deformation, a gap is generated between the work 7 (8) and the mask 92. When the gap is larger than the conductive ball 6, the conductive ball leaks from the gap and becomes an excess ball indicated by reference numeral 6 c in the figure, which causes a short circuit of the conductor pattern. Further, as indicated by reference numeral 6b in the figure, the conductive balls 6b leaking from the gap adhere to the outer peripheral portion of the pad electrode 72 (82), and the conductive balls 6b are connected to each other to form a bridge. When the workpiece 7 (8) in which connection failure such as a short circuit or a bridge is caused is incorporated in the electronic component 5, there is a problem that the reliability of the electronic component 5 is lowered.

  The present invention has been made by the inventors of the present invention in order to solve the above problems, and the object thereof is to manufacture the connection bumps formed on the semiconductor element, the wiring board and the electronic component package. It is an object of the present invention to provide a conductive ball mounting apparatus and mounting method capable of preventing the occurrence of poor connection and to supply more reliable electronic components to the market.

  The conductive ball mounting apparatus according to the present invention employs a conductive ball as a connection bump, and the workpiece is arranged with a pad electrode arranged in a predetermined pattern and the surface on which the pad electrode is arranged facing upward. A table to be placed; and a mask corresponding to the arrangement pattern of the pad electrodes and having a positioning opening through which the conductive ball can be inserted; and the mask faces the surface on which the pad electrodes are arranged And the positioning opening is aligned with the pad electrode, and the conductive ball is mounted on the pad electrode through the positioning opening, and the table sucks the aligned mask. In addition, it is characterized in that a vacuum suction means is provided for bringing the pad electrode into close contact with the arrayed surface. The vacuum suction means is preferably configured to suck the mask in the outer peripheral area of the mask that does not face the workpiece.

  The conductive ball mounting apparatus according to the present invention employs a conductive ball as a connection bump, and corresponds to a work in which pad electrodes are arranged in a predetermined pattern, and the arrangement pattern of the pad electrodes of the work, and the conductive A mask in which a positioning opening through which a ball can be inserted is formed, the mask is made to face the surface on which the pad electrode is arranged, the positioning opening is aligned with the pad electrode, and the positioning is performed. A mounting method in which the conductive ball is mounted on the pad electrode through an opening, wherein the aligned mask is sucked to the work side by negative pressure, and the mask is adhered to a surface on which the pad electrode is arranged It is characterized by letting

  According to the mounting device of the present invention, a positioning opening corresponding to the arrangement pattern of the pad electrodes and capable of inserting the conductive balls is formed on the workpiece with the surface on which the pad electrodes are arranged facing upward. The mask faces the surface on which the pad electrodes are arranged, the positioning opening is aligned with the pad electrode, is sucked by the vacuum suction means, and is in close contact with the connection surface. Therefore, there is no gap between the surface on which the pad electrodes are arranged and the mask, and it is possible to prevent the occurrence of connection failures such as a short circuit of a work due to conductive balls leaking from the gap and a bridge between connection bumps, It becomes possible to improve the reliability of the electronic component in which the workpiece is incorporated.

  The conductive ball mounting apparatus and mounting method of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an aspect of the mounting apparatus of the present invention. 2A and 2B are diagrams for explaining a main part of FIG. 1, in which FIG. 2A is a partially enlarged plan view of the mask, and FIG. 2B is an enlarged sectional view of the mask. FIG. 3 is a view for explaining a method of manufacturing a connection bump by mounting a conductive ball using the mounting apparatus of FIG. FIG. 4 is a diagram for explaining the detailed structure of the table of FIG. Hereinafter, a case where a solder ball is used as the conductive ball will be described as an example. However, the present invention can be similarly applied to a conductive ball such as a copper ball used for forming a connection bump. .

  As shown in FIGS. 1 and 2, the mounting apparatus 1 of the present invention employs at least a work 7 (8) in which solder balls 6 are employed as connection bumps 83 and pad electrodes 72 (82) are arranged in a predetermined pattern. Corresponding to the arrangement pattern of the table 11 on which the work 7 (8) is placed with the surface on which the pad electrodes 72 (82) are arranged (hereinafter referred to as the connection surface) facing upward, and the arrangement pattern of the pad electrodes 72 (82), And a mask 12 having a positioning opening 123 into which the solder ball 6 can be inserted. The mask 12 faces the connection surface, and the positioning opening 123 is aligned with the pad electrode 72 (82). In the mounting device 1 for mounting the solder ball 6 on the pad electrode 72 (82) through the opening 123, the table 11 sucks the aligned mask 12 and connects the connection And a mask suction means is brought into close contact.

  As shown in FIG. 2, the mask 12 is formed in accordance with the arrangement pattern of the pad electrodes 72 (82), and has a positioning opening 123 through which the solder ball 6 can be inserted. The material of the mask 12 can be appropriately selected from metals such as stainless steel and nickel, or resins such as polyethylene and polyester as necessary.

  The mask 12 may be attached and detached manually. For example, one end of the mask 12 is supported by a mask moving means that moves laterally on the paper surface as indicated by reference numeral 13 in FIG. In this case, the workpiece is positioned above the workpiece 7 (8), and when the wiring board 8 is removed from the table 11, as shown in FIG. 1B, the workpiece 7 (8) is detached from above. This is desirable because the mask 12 can be positioned efficiently.

  The table 11 includes a magnetism generator for generating magnetism, denoted by reference numeral 113 in FIG. The magnetic generator 113 is built in the table 11 so as to face the mask 12 placed above the connection surface of the wiring board 8, and serves as a power supply control unit that is provided outside the table 11 and supplies power to the magnetic generator 113. It is connected. The magnetic generator 113 is powered by the power feeding control means to attract the mask 12 placed above the workpiece 7 (8) by magnetic force, and the lower surface of the mask 12 is attached to the connection surface of the workpiece 7 (8). Adhere closely. Therefore, when the magnetism generator 113 is used as the mask attracting means, it is desirable that the mask 12 is formed of a magnetic material that can attract at least the facing surface (lower surface) of the connection surface by a magnetic force.

Further, as shown in FIG. 4B, the table 11 is disposed in the same manner as the magnetism generator 113 as mask suction means, and is printed on the positive electrode or the negative electrode by a printing pressure control means provided outside. The electrostatic force generator 114 may be provided. The electrostatic force generation device 114 is applied with a polarity opposite to the polarity of the pressure applied to the mask 12 placed above via the work 7 (8) by being printed with a positive or negative electrode by the printing pressure control means. Charging is performed, and the mask 12 is attracted by electrostatic force, and the lower surface of the mask 12 is brought into close contact with the connection surface of the workpiece 7 (8). Therefore, when the electrostatic force generator 114 is used as the mask suction means, the mask 12 is desirably formed of a material that is easily charged. For example, the dielectric constant is 4 to 12 and the dielectric constant is relatively high, and the electrical resistivity is 10. Insulating materials having conductivity of about ⁸ to 10 ¹² Ωcm, specifically, polyimide resin, phenol resin, silicon resin, vinyl chloride resin, ABS resin, acetylcellulose, acetylbutylcellulose, urethane elastomer, chloroprene rubber, nitrile rubber and It is preferable to select a mixture of these or a mixture of them with carbon black as appropriate.

  Furthermore, as shown in FIG. 4C, the table 11 has an opening 111a that opens on the upper surface of the table 11 other than the portion on which the workpiece 7 (8) is placed, and an opening on the side surface as mask suction means. An opening 111b, a fluid passage 111 that connects the openings 111a and 111b and is defined in the table 11, and a vacuum suction device 115 that includes a vacuum generation unit connected to the opening 111b. It may be. The vacuum suction means 115 generates a negative pressure by the vacuum generation means, sucks the mask 12 placed above the table 11 through the fluid passage 111 with a negative pressure, and the mask 12 is attached to the connection surface of the workpiece 7 (8). Adhere the bottom surface.

  According to the mask suction means, as shown in FIG. 6 (b), the mask 12 is sucked to the mask suction means side through the work 7 (8), and the connection follows the deformation of the work 7 (8). Since it is in close contact with the surface, there is no gap between the workpiece 7 (8) and the mask 12. Therefore, the solder ball 6 mounted on the pad electrode 72 (82) through the positioning opening 123 can hold the mounted position without leaking from the gap.

  The positioning of the table 11 may be performed manually. For example, the table 11 is connected to a table lifting / lowering means indicated by reference numeral 19 in FIG. When the table 11 is raised to a predetermined position and the solder ball 6 is mounted, the table 11 is lowered as shown in FIG. This is desirable because it can be done.

  The means for supplying solder balls 6, that is, means for supplying more solder balls 6 than the number of positioning openings 123 to the upper surface of the mask 12 positioned above the connection surface of the workpiece 7 (8) is particularly limited. However, for example, as shown in FIG. 1 (a), a solder ball supply means 14 having a supply port 141 disposed above the right end (one end) of the mask 12 is provided to supply the solder ball. It is preferable to supply the solder balls 6 by the means 14 in a fixed quantity because the solder balls 6 can be supplied efficiently.

  The configuration of the transfer means for transferring the solder ball 6 supplied to the mask 12 into the positioning opening 123 is not particularly limited. For example, as indicated by reference numeral 15 in FIG. A flexible spatula or brush-like one that can traverse while the upper surface and the tip of the mask 12 are in contact between the right end (one end) and the left end (the other end) may be used. According to the transfer means 15, the solder balls 6 supplied to the upper surface of the mask 12 are captured at the tip of the transfer means 15, moved between both ends of the mask 12, and sequentially inserted into the positioning opening 123. It will be.

  The means for removing the solder ball 6, that is, the means for removing the remaining solder ball 6 not inserted into the positioning opening 123 from the upper surface of the mask 12 is not particularly limited. For example, as shown in FIG. Thus, the solder ball removing means 16 having the supply port 162 disposed above the left end (the other end) of the mask 12 is provided, and the remaining solder balls 6 moved to the left end by the transfer means 15 are provided. It is desirable to remove the solder ball 6 by the solder ball supply means 16 because the solder ball 6 can be efficiently removed.

  The mounting method of the solder ball 6 by the mounting device 1 having such a configuration employs the solder ball 6 as the connection bump 83 and the work 7 (8) in which the pad electrodes 72 (82) are arranged in a predetermined pattern, and the work 7 ( 8) corresponding to the arrangement pattern of the pad electrodes 72 (82), and the mask 12 having the positioning openings 123 into which the solder balls 6 can be inserted, and the workpiece 7 (8) in which the pad electrodes 72 (82) are arranged. ) With the mask 12 facing the connection surface above, positioning the positioning opening 123 to the pad electrode 72 (82), and mounting the solder ball 6 on the pad electrode 72 (82) through the positioning opening 123. In this method, the aligned mask 12 is sucked toward the workpiece 7 (8), and the mask 12 is brought into close contact with the connection surface. Hereinafter, the mounting method of the solder ball 6 will be described in detail with reference to FIG.

[Mask insertion process]
A mask 12 made of a magnetic material is prepared. As shown in FIG. 3A, positioning is performed so that the lower surface of the mask 12 faces upward with respect to the connection surface of the workpiece 7 (8), and the positioning opening 123 is aligned with the pad electrode 72 (82). In the positioning, the mask 12 may be positioned in a state of being separated from the connection surface by a gap appropriately set according to the magnitude of the magnetic force (attraction force) generated by the magnetism generator 113, You may position in the state contact | abutted with the said connection surface. Next, power is supplied to the magnetism generator 113, and the mask 12 is attracted toward the workpiece 7 (8) by the magnetic force, and the lower surface of the mask 12 is brought into close contact with the connection surface. In order to prevent the mounted solder ball 6 from being detached from the pad electrode 72 (82) as needed, a temporary fixing material for temporarily fixing the solder ball 6 having an appropriate viscosity, such as solder paste or flux. May be provided before the mask insertion step.

[Solder ball mounting process]
As shown in FIG. 3B, the solder balls 6 equal to or more in number than the positioning openings 123 are supplied to the upper surface of the mask 12, and the solder balls 6 are swung into the positioning openings 123. The remaining solder balls 6 are removed from the upper surface of the mask 12. If necessary, in order to prevent the mounted solder ball 6 from being detached from the pad electrode 72 (82), for example, the mounted solder ball 6 is pressed against the pad electrode 72 (82), and the pad electrode 72 ( 82) may be provided after the solder ball mounting step.

[Mask removal process]
As shown in FIG. 3C, power supply to the electromagnetic coil device 113 is turned off, and the mask 12 is removed.

  Thereafter, as shown in FIG. 3D, if the solder balls 6 mounted on the pad electrodes 72 (82) are reflowed by an appropriate method, a desired connection bump 83 is formed.

It is a schematic block diagram which shows an example of the mounting apparatus of the conductive ball of this invention. It is the elements on larger scale which show the detail of the mask of the mounting apparatus of FIG. It is a figure explaining the mounting method of the conductive ball by the mounting apparatus of FIG. It is a figure which shows the detail of the table of the mounting apparatus of FIG. It is a figure which shows the structure of a BGA or CSP type package. It is a figure explaining the state in which the conductive ball was mounted by the conventional method.

Explanation of symbols

1: mounting device, 11: table, 12: mask 4: package 5: electronic component 7: semiconductor element, 72: pad electrode 8: wiring board, 82: pad electrode, 83: connection bump

Claims (3)

  Conductive balls are used as connection bumps, a work in which pad electrodes are arranged in a predetermined pattern, a table on which the work is placed with the surface on which the pad electrodes are arranged facing upward, and an arrangement pattern of the pad electrodes And a mask having a positioning opening through which the conductive ball can be inserted, the mask facing the surface on which the pad electrode is arranged, and the positioning opening on the pad electrode. A mounting device for aligning and mounting the conductive ball on the pad electrode through the positioning opening, wherein the table sucks the aligned mask and adheres to the surface on which the pad electrode is arranged A mounting apparatus characterized by comprising vacuum suction means.   The mounting apparatus according to claim 1, wherein the vacuum suction unit sucks the mask in an outer peripheral region of the mask that does not face the workpiece.   Conductive balls are used as connection bumps, and a work in which pad electrodes are arranged in a predetermined pattern and a positioning opening through which the conductive balls can be inserted are formed corresponding to the arrangement pattern of the pad electrodes of the work. The mask is opposed to the surface on which the pad electrode is arranged, and the positioning opening is aligned with the pad electrode, and the conductive ball is placed on the pad electrode through the positioning opening. A mounting method for mounting, wherein the aligned mask is sucked to the workpiece side by negative pressure, and the mask is brought into close contact with a surface on which the pad electrodes are arranged.

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