JP2008186968A - Ball arrangement mask - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ball arrangement mask which minimizes strain due to tension, even when the ball arrangement mask is stuck to a rectangular frame-like frame by tension, by forming the outer-periphery shape of an entire recess formed in a ball mount region of the ball arrangement mask nearly in a circular shape. <P>SOLUTION: The following means are adopted for the ball arrangement mask. More specifically, at first, the ball arrangement mask is pasted to the rectangular frame by tension via a flexible sheet, and has a mount region where a through hole for inserting balls is provided according to the mounted part of an object to be mounted formed in a prescribed arrangement pattern and a non-mount region for surrounding the mount region. Next, the mount region is formed as a recess including the mount region and the through hole is provided in the recess. Then, in the ball arrangement mask, the outer periphery of the entire recess formed in the mount region is formed nearly in a circular shape. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a ball array mask, and more particularly, a ball array mask used in an apparatus for mounting conductive balls, in which a ball insertion through hole is formed corresponding to a mounting location of an object to be mounted. It relates to an array mask.

  A ball array mask in which through holes for ball insertion are formed in an array pattern corresponding to the mounting location is placed on a semiconductor wafer, which is a mounting object on which flux is printed, and solder balls are placed directly on the electrodes of the semiconductor wafer. A device to be mounted as a drop has been conventionally provided as shown in Patent Document 1.

  However, in recent years, with the miniaturization of the mounted balls, it has become necessary to make the ball arrangement mask thinner. When the entire ball arrangement mask is thinned, the strength is weakened. Therefore, only the region corresponding to the mounting portion on which the electrode of the semiconductor wafer is formed is thinly processed using a method such as etching to form a recess. In order to correct the distortion generated in the ball arrangement mask during the processing of the recesses, the ball arrangement mask was attached to a rectangular frame-like frame so as to be pulled outward as shown in Patent Document 2 ( Patent Document 2, paragraph 0016). As described above, even when the ball arrangement mask is attached to the rectangular frame-shaped frame with tension, distortion due to the difference in thickness due to the concave portion formed in the ball arrangement mask is generated.

  Furthermore, the ball arrangement mask may be affixed to a large frame in order to improve the versatility of the apparatus. In such a case, the ball arrangement mask becomes larger than necessary, and bending due to its own weight often occurs. It was.

Japanese Patent Laid-Open No. 2006-302921 Japanese Patent Application Laid-Open No. 8-192585

  The present invention can also be applied to the case where the ball arrangement mask is applied with tension to a rectangular frame frame by forming the outer peripheral shape of the entire recess formed in the ball mounting area of the ball arrangement mask into a substantially circular shape. An object of the present invention is to provide a ball array mask capable of minimizing distortion due to tension. Furthermore, in the second invention, an attempt is made to provide a ball arrangement mask capable of increasing the strength of the ball arrangement mask and suppressing the deflection by providing the concave portions with continuous protrusions from the non-mounting area to the non-mounting area. To do.

In order to solve the above problems, the first invention employs the following means for the ball array mask.
First, a through hole for inserting a ball is provided corresponding to a mounting position of an object to be mounted formed in a predetermined arrangement pattern, which is attached to a frame-like frame with tension through a flexible sheet. A ball array mask having a mounted area and a non-mounted area surrounding the mounted area.
Second, the mounting area is formed as a recess including the mounting area, and the ball array mask is provided with the through hole in the recess.
Thirdly, a ball array mask in which the outer peripheral shape of the entire recess formed in the mounting area is formed in a substantially circular shape.

  A second invention is a ball array mask in which means for providing a convex portion continuous from the non-mounting region to the non-mounting region is provided in the concave portion in the first invention.

  According to a first aspect of the present invention, in the ball arrangement mask in which the mounting area of the ball arrangement mask is formed as a recess including the mounting area, and the through hole is provided in the depression, the entire depression formed in the mounting area Since the outer peripheral shape of the lens is formed in a substantially circular shape, even when the ball arrangement mask is applied to a rectangular frame-shaped frame with tension applied, the direction of tension is balanced and the occurrence of distortion can be suppressed. It became possible.

  In the second aspect of the invention, since the concave portion is further provided with a convex portion continuous from the non-mounting region to the non-mounting region, the strength of the ball arrangement mask can be increased and the deflection can be suppressed. It was.

Hereinafter, embodiments of the present invention will be described together with examples according to the drawings.
The embodiment relates to a solder ball mounting apparatus. Of course, the present invention can also be used in other conductive ball mounting apparatuses in which conductive balls are mounted on the respective electrodes formed in a predetermined array pattern on the mounting target. In the present invention, the ball includes a conductive ball such as a solder ball, and the ball mounting object includes a semiconductor wafer (hereinafter simply referred to as a wafer), an electronic circuit substrate, a ceramic substrate, and the like. In this embodiment, the solder balls 4 are used as balls, and the wafer 8 is used as a ball mounting object.

  Usually, a solder ball mounting apparatus has a wafer transfer section for loading, a flux printing section, a ball mounting section, and a wafer transfer section for unloading, but the ball arrangement mask according to the present invention exists in the ball mounting section. In addition, the through holes 10 arranged in accordance with the electrode pattern on the wafer 8 are formed. Further, as shown in FIGS. 1 and 4, the ball mounting portion 25 holds the solder ball supply device 1, the support device 3 of the ball arrangement mask 2 and the wafer 8 by suction, and can move up and down to a wafer mounting table 25. And are deployed.

  The solder ball supply device 1 includes a ball hopper (not shown) that stores a large number of solder balls 4, and a ball cup 5 that houses the solder balls 4 that are dropped into the through holes 10 of the ball arrangement mask 2 shown in FIG. And an X-axis moving device 6 and a Y-axis moving device 7 for moving the ball cup 5 in the X-axis direction and the Y-axis direction, and the ball cup 5 is moved on the ball array mask 2, and FIG. As shown, the solder balls 4 are dropped into the through holes 10 of the ball array mask 2 and the solder balls 4 are mounted on the electrodes at the mounting locations 9 on the wafer 8. The traveling direction for the ball cup 5 to drop the solder ball 4 into the through hole 10 is the front-rear direction in the drawing in FIG. 5 and the up-down direction in the drawing in FIG.

  As shown in FIG. 5, the ball array mask 2 is provided with through holes 10 for ball insertion corresponding to the mounting locations 9 of the wafer 8. The through holes 10 correspond to a predetermined arrangement pattern of the mounting locations 9 formed in the wafer 8. 2 and 3, a large number of rectangular figures appearing in the center are exaggerated in the die size region 23, and a large number of through holes 10 exist in the die size region 23.

  A reference numeral 11 indicated by a dotted line in FIGS. 1 and 2 is a mounting region in which the through hole 10 is formed. The ball array mask 2 includes a mounting region 11 and a non-mounting region 12 surrounding the mounting region 11. Exists. The back surface side of the ball array mask 2 in the mounting area 11 (the side facing the wafer 8) is formed thin as a recess 13 that covers the entire area of the mounting area 11, and the through hole 10 is provided in the recess 13. It has been. The diameter of the through hole 10 of the ball arrangement mask 2 is formed slightly larger than the diameter of the solder ball 4.

  The concave portion 13 formed in the mounting region 11 is slightly larger than the outer shape of the wafer 8 as a whole, and the outer peripheral shape of the entire concave portion 13 is formed in a substantially circular shape. When the ball arrangement mask 2 is attached to the rectangular frame 16 with tension, the ball arrangement mask 2 is pulled in the left-right front-rear direction (up, down, left-right direction in FIGS. 2 and 3). Since the outer peripheral shape of each is formed in a substantially circular shape, the tension in the left-right front-rear direction is converted into an average tension in the circular outer direction, and distortion due to the tension hardly occurs.

  The amount of the recess 13 differs depending on the diameter of the solder ball 4 used. In the embodiment, since the solder balls 4 having a thickness of about 100 micrometers are used, the recesses 13 having a thickness of 20 to 40 micrometers are formed in the ball array mask 2 having a thickness of 80 micrometers.

  Further, as shown in FIG. 3, the concave portion 13 is provided with a convex portion 14 that continues from the non-mounting area 12 on the near side to the non-mounting area 12 on the other side. That is, the convex part 14 is connected to the front and rear edge parts of the concave part 13 in the forming direction. The convex portion 14 is formed at the position corresponding to the dicing line in one direction of the wafer 8 and in the same direction as the traveling direction for the ball cup 5 to drop the solder ball 4 into the through hole 10. Here, the advancing direction of the ball cup 5 means the front-rear direction in the drawing in FIG. 5, and the up-down direction in the drawing in FIG. The convex portion 14 is formed of the same material as that of the ball arrangement mask 2. By providing the convex portion 14, the strength of the thin ball array mask 2 can be increased, and the ball array mask 2 becomes difficult to bend. Regarding the thickness of the ball array mask 2, the total thickness of the mounting area 11 in which the concave portion 13 is formed and the protruding thickness of the convex portion 14 is made thinner than the diameter of the solder ball 4 to be used. In addition, the thickness of the non-mounting area | region 12 may be equal to the sum of the plate | board thickness of the mounting area | region 11 in which the recessed part 13 was formed, and the protrusion thickness of the convex part 14, and may be thicker than this sum.

  As shown in FIG. 3 and FIGS. 5 to 6, a reinforcing thin plate 22 in which a portion corresponding to the mounting area 11 of the ball arrangement mask 2 is formed in an empty portion is bonded to the back surface of the ball arrangement mask 2 in the embodiment. ing. Thereby, the intensity | strength of the ball | bowl arrangement | sequence mask 2 can be improved more and distortion and bending can be suppressed. The reinforcing thin plate 22 is appropriately formed with an opening hole so that bubbles and excess adhesive during bonding can be removed.

  The ball array mask 2 is affixed to a combination 15 which is a flexible resin sheet, and is attached to a rectangular frame 16 with tension applied thereto. The frame 16 is an air cylinder for clamping. 17 is fixed to the ball mounting portion constituting frame of the apparatus. There are several fixed points.

  The support device 3 for the ball array mask 2 includes a mask support 31, a mask support holder 32, an air cylinder 33 that moves the mask support 31 up and down, a suction device (not shown), and a support member 21 for the ball array mask 2. The support member 21 is disposed below the contact surface 18 of the mask support 31, and the ball array mask 2 is placed on the support member 21 with the lower surface of the reinforcing thin plate 22 of the ball array mask 2 in contact with the upper surface. The upper surface is sucked and held by the mask support 31. At this time, the ball array mask 2 is supported by the mask support 31 in a state where the convex portion 14 formed in the concave portion 13 of the mounting region 11 does not contact the surface of the wafer 8.

  The mask support 31 is a rectangular frame-shaped body whose center is a rectangular hollow portion having a size corresponding to the mounting area 11 of the ball array mask 2. The lower surface of the frame of the mask support 31 is a contact surface 18 to the non-mounting region 12 surrounding the mounting region 11 of the ball arrangement mask 2 and is formed on a flat surface with high flatness. A suction groove 19 for sucking the ball array mask 2 is formed on the contact surface 18. Further, the suction groove 19 is connected to an external suction device (not shown) by a suction pipe 20. The ball array mask 2 is sucked and supported by the suction force from the suction groove 19.

  The mask support 31 is held by the upper and lower air cylinders 33 via mask support holders 32 installed at a plurality of left and right locations, and the hollow portion of the mask support 31 corresponds to the mounting area 11 of the ball array mask 2. The contact surface 18 of the mask support 31 is disposed so as to contact the upper surface of the non-mounting region 12 surrounding the entire mounting region 11. The ball array mask 2 sucked and supported by the contact surface 18 of the mask support 31 is in a state free from distortion at least inside the contact surface 18.

Plane explanatory drawing of the ball mounting part in the solder ball mounting apparatus concerning a present Example Plane explanatory diagram of the ball array mask with the frame attached Bottom view of ball array mask with frame attached Explanatory drawing which shows the relationship between a ball cup, a ball arrangement | sequence mask, and a support apparatus. Explanatory drawing which shows the relationship between a wafer, a solder ball, and a ball arrangement mask Explanatory drawing observing support device and ball array mask from below

Explanation of symbols

1. . . . . . 1. Ball supply device . . . . . 2. Ball array mask . . . . . 3. Support device . . . . . 4. Solder balls . . . . . Ball cup 6. . . . . . X-axis moving device 7. . . . . . Y axis moving device 8. . . . . . Wafer 9. . . . . . Mounting location 10. . . . . Through hole 11. . . . . Mounting area 12. . . . . Non-mounting area 13. . . . . Concave part 14. . . . . Convex part 15. . . . . Combination 16. . . . . Frame 17. . . . . Air cylinder for clamping 18. . . . . Contact surface 19. . . . . Adsorption groove 20. . . . . Suction pipe 21. . . . . Support member 22. . . . . Thin plate for reinforcement 23. . . . . Die size area 25. . . . . Wafer mounting table 31. . . . . Mask support 32. . . . . Mask support holder 33. . . . . Air cylinder

Claims (2)

A mounting area in which a through hole for inserting a ball is provided corresponding to a mounting position of an object to be mounted formed in a predetermined arrangement pattern, which is attached to a frame-like frame with tension through a flexible sheet. And a ball array mask having a non-mounting area surrounding the mounting area,
The mounting area is formed as a recess including the mounting area, and the outer peripheral shape of the entire recess formed in the mounting area is formed in a substantially circular shape in the ball arrangement mask in which the through hole is provided in the recess. A ball array mask characterized by that.
  2. The ball arrangement mask according to claim 1, wherein the concave portion is provided with a convex portion continuous from the non-mounting region to the non-mounting region.

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