Solder ball attaching system and method

• US 6,607,117 B1
• Filed: 10/16/2000
• Issued: 08/19/2003
• Est. Priority Date: 10/15/1999
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kang, Ju-Il, Yang, Hee-Sang
• Primary Examiner(s): Dunn, Tom
• Assistant Examiner(s): Tran, Len
• Application Number:
  US09/690,683
• Time in Patent Office: 1,037 Days
• Field of Search: 228/6.2, 228/8, 228/9, 228/10, 228/33, 228/49.5, 228/103, 228/105, 228/245, 228/246, 228/205, 228/207, 228/223
• US Class Current: 228/103
• CPC Class Codes: B23K 1/0016 Brazing of electronic components
• CPC Class Codes: B23K 1/203 Fluxing, i.e. applying flux onto surfaces
• CPC Class Codes: B23K 1/206 Cleaning
• CPC Class Codes: B23K 2101/42 Printed circuits
• CPC Class Codes: B23K 3/0623 for shaped solder piece feeding, e.g. preforms, bumps, balls, pellets, droplets
• CPC Class Codes: B23K 3/08 Auxiliary devices therefor cleaning pipes or tubes or systems of pipes or tubes, e.g. before soldering, B08B9/02
• CPC Class Codes: B23K 3/082 Flux dispensers; Apparatus for applying flux
• CPC Class Codes: H01L 23/49816 Spherical bumps on the substrate for external connection, e.g. ball grid arrays [BGA]
• CPC Class Codes: H01L 24/11 Manufacturing methods for bumps on insulating substrates H01L21/4853
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H05K 3/3478 Applying solder preforms; Transferring prefabricated solder patterns

Abstract

The disclosure is a plural process to perform a solder ball attaching process that corresponds to the final of a ball grid array package manufacturing process. For example, flux and solder balls are exactly attached on solder ball pads of base frames on which base tapes having a number of land pattern groups are adhered. In the above state, the base frames are inserted into an adjacent reflow device to make the solder balls be attached on the solder ball pads. After the flux of the solder ball pad, on which the solder ball is attached, is removed, the base frames are stored in containers. To perform the base frame storing process in a very small space, the transfer course of the base frames is in the form of loop.

Claims

1. A system for attaching solder balls, the system comprising:

a base body;

a base frame unloader for unloading base frames from containers mounted on the base body to seat the solder balls on solder ball pads of the base frames;

a solder ball seating device mounted on the base body, the solder ball seating device receiving the unloaded base frames from the base frame unloader, fixing the base frames in a designated position, coating with flux, seating the solder balls, sorting the base frames and storing some of the base frames;

a reflow device mounted on the base body, the reflow device loading the sorted and stored base frames and melting and cooling the solder balls;

a cleaning device mounted on the base body, the cleaning device receiving the loaded base frames from the reflow device, cleaning the flux remaining on the solder ball pads and drying the base frames; and

a base frame loader mounted on the base body, the base frame loader sorting the base frames transferred from the cleaning device and storing some of the base frames.

2. The system as claimed in claim 1, wherein the base frame unloader, the solder ball seating device, the reflow device, the cleaning device and the base frame loader are mounted on the base body in such a manner that the base frames are circulated in a circle.

3. The system as claimed in claim 2, wherein the containers are stored inside the base body, and empty containers from which the base frames are all unloaded are transferred to the base frame loader mounted at a place adjacent to the base frame unloader.

4. The system as claimed in claim 3, wherein the base frame unloader includes:

a container guider formed to extend from an upper portion of the base body to the inside of the base body;

a container elevator for lifting the containers stored in the inside of the base body from the inside of the base body upward along the container guider; and

a pusher discharging the base frames from the containers mounted on the container guider.

5. The system as claimed in claim 1, wherein the solder ball seating device includes:

a composite unit for receiving, fixing and transferring the base frames unloaded from the base frame unloader;

a flux coating unit for coating the solder ball pads of the base frames fixed on the composite unit with flux;

a solder ball seating unit for seating the solder balls on the solder ball pads coated with the flux by the flux coating unit;

a transfer unit for transferring the flux coating unit and the ball seating unit to the solder ball pads fixed on the composite unit;

a sorter unit receiving the base frames on which the flux and the solder balls are seated, the sorter unit sorting and storing base frames according to quality of solder ball seating; and

a waiting unit making some of the base frames, which are sorted and stored by the sorting unit, wait until a next step is performed.

6. The system as claimed in claim 5, wherein the composite unit includes:

a transfer belt type transfer unit receiving the base frames, which are discharged from the base frame unloader, by a transfer belt, the transfer belt type transfer unit relaying the base frames to the sorter unit; and

a fixed unit having a base frame adsorption pad for adsorbing a lower surface of the base frames, which are transferred by the transfer belt type transfer unit, with vacuum pressure, and an up-down cylinder for contacting and separating the base frame adsorption pad to and from the lower surface of the base frames.

7. The system as claimed in claim 5, wherein the flux coating unit includes:

a support rod transferred by the transfer unit;

an up-down cylinder connected to an end of the support rod, the up-down cylinder having a cylinder rod moving vertically;

a bracket mounted at an end of the cylinder rod;

a flux coating block detachably connected to the bracket, the flux coating block having flux coating pins formed to have the same shape and position as the solder ball pads; and

a flux feeding tray coated with flux in such a manner that the flux is coated on the flux coating pins by the up-down cylinder.

8. The system as claimed in claim 7, wherein the flux feeding tray includes:

a coating block supplied with a small amount of flux to coat a bottom surface of the flux feeding tray with the flux; and

a coating block transfer device for making the coating block reciprocate.

9. The system as claimed in claim 7, wherein the solder ball seating unit includes:

a support rod transferred by the transfer unit;

an up-down cylinder connected to an end of the support rod, the up-down cylinder having a rod moving vertically;

a bracket mounted at an end of the cylinder rod;

a solder ball adsorption pad detachably connected to the bracket, the solder ball adsorption pad having a vacuum pressure forming space inside and solder ball storing holes, which have the same shape and position as the solder ball pads and communicate with the vacuum pressure forming space; and

a solder ball receiving tray storing a number of solder balls in such a manner that the solder balls are adsorbed in the solder ball storing holes of the solder ball adsorption pad in which vacuum pressure is formed by the up-down cylinder.

10. The system as claimed in claim 7 or 9 wherein the transfer unit includes:

a support frame mounted across the composite unit and having a prescribed height from the upper surface of the base body, the support frame having two long through holes of a slit shape formed from both ends toward the center, wherein the support rods are inserted into the through holes respectively;

a transfer screw screwed with the support rod;

a bushing supporting both ends of the transfer screw; and

a driving device connected one of the ends of the transfer screw to rotate the transfer screws.

11. The system as claimed in claim 5, wherein the sorter unit includes:

a sorter receiving the base frames, on which the solder balls are attached, from the composite unit to unload the base frames in a designated position while moving along a designated course;

a visual inspection unit for inspecting seating quality of solder ball of the base frames stored in the sorter; and

containers for storing some of the base frames as determined by the visual inspection unit.

12. The system as claimed in claim 1, wherein the reflow unit includes:

a base frame feeder for loading the base frames, on which the solder balls are seated by the solder ball seating unit;

a step transfer device for transferring the base frames;

a chamber enclosing the step transfer device;

a heating device mounted at an inner surface of an outlet of the chamber located opposite the step transfer device; and

a cooling fan mounted at the inner surface of an inlet of the chamber separated from the heating device.

13. The system as claimed in claim 12, wherein the step transfer device includes:

a plurality of base frame guide rails extending in the longitudinal direction of the inner surface of the chamber, the base frame guide rails being of a width on the upper surface to support both ends of the base frames;

transfer bars transferring the base frames seated on the base frame guide rails while moving along the upper surface of the base frame guide rails;

sprocket wheel assemblies mounted at both ends of the base frames guide rails to drive the transfer bars; and

transfer chains connected to the sprocket wheel assemblies and with the bars.

14. The system as claimed in claim 13, wherein the transfer device includes:

a transfer screw extending from the outlet of the chamber to the cleaning device;

a bushing for supporting both ends of the transfer screw;

a motor mounted at one of the ends of the transfer screw to rotate the transfer screw;

a transfer block screwed with the transfer screw, the transfer block moving along the transfer screw by the driving of the motor; and

a pick-up module connected to the transfer block, the pick-up module transferring the base frame discharged to the outlet of the chamber.

15. The system as claimed in claim 1, wherein the cleaning device includes:

a transfer device receiving the base frames discharged from the reflow device and transferring the base frames;

a cleaning chamber enclosing the transfer device;

a cleaning solution feeding device mounted inside the cleaning chamber, the cleaning solution feeding device being mounted across upper and lower portions of the transfer device;

a dryer device for drying the base frames cleaned by the cleaning solution feeding device; and

an unloader for unloading the dried base frames.

16. The system as claimed in claim 15, wherein the transfer device includes:

a plurality of base frame guide rails extending in a longitudinal direction of an inner surface of the cleaning chamber, the base frame guide rails being of a width on an upper surface to support both ends of the base frames;

transfer bars transferring the base frames seated on the base frame guide rails while moving along the upper surface of the base frame guide rails;

sprocket wheel assemblies mounted at both ends of the base frame guide rails to drive the transfer bars; and

transfer chains connected to the sprocket wheel assemblies and with the transfer bars.

17. The system as claimed in claim 15, wherein the cleaning solution feeding device includes:

two cleaning solution pipes disposed across the upper and lower portions of the transfer device in rows, the cleaning solution pipes being supplied with pure water; and

cleaning solution injecting nozzles for injecting pure water from the cleaning solution pipes.

18. The system as claimed in claim 15, wherein the dryer device includes;

two air knives disposed across the upper and lower portions of the transfer device in the air knives injecting high-temperature dried air; and

a high-temperature dried air feeding device for supplying the high-temperature dried the air knives.

19. The system as claimed in claim 1 wherein the base frame loader includes:

a base frame transfer device receiving the base frames unloaded from the cleaning device, the base frame transfer device transferring the base frames according to quality of solder ball attachment on the solder ball pads and sorting and storing the base frames;

a visual inspection unit receiving the base frames and inspecting the quality of solder ball attachment on the solder ball pads; and

containers for storing the base frames sorted by the base frame transfer device.