WO1999017594A1 - Laser reflow with template for solder balls of bga packaging - Google Patents
Laser reflow with template for solder balls of bga packaging Download PDFInfo
- Publication number
- WO1999017594A1 WO1999017594A1 PCT/SG1998/000055 SG9800055W WO9917594A1 WO 1999017594 A1 WO1999017594 A1 WO 1999017594A1 SG 9800055 W SG9800055 W SG 9800055W WO 9917594 A1 WO9917594 A1 WO 9917594A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- laser
- template
- pads
- reflow
- solder
- Prior art date
Links
- 229910000679 solder Inorganic materials 0.000 title claims abstract description 58
- 238000004806 packaging method and process Methods 0.000 title claims abstract description 18
- 239000000758 substrate Substances 0.000 claims abstract description 19
- 230000004907 flux Effects 0.000 claims abstract description 13
- 238000005476 soldering Methods 0.000 claims description 12
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 4
- 239000011159 matrix material Substances 0.000 claims description 3
- 230000000007 visual effect Effects 0.000 claims description 3
- 229910052757 nitrogen Inorganic materials 0.000 claims description 2
- 238000007599 discharging Methods 0.000 claims 2
- 238000005498 polishing Methods 0.000 claims 1
- 230000000063 preceeding effect Effects 0.000 claims 1
- 238000000034 method Methods 0.000 abstract description 13
- 238000002844 melting Methods 0.000 abstract description 3
- 230000008018 melting Effects 0.000 abstract description 3
- 238000007796 conventional method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000006073 displacement reaction Methods 0.000 description 3
- 239000013307 optical fiber Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000012858 packaging process Methods 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- JNDMLEXHDPKVFC-UHFFFAOYSA-N aluminum;oxygen(2-);yttrium(3+) Chemical compound [O-2].[O-2].[O-2].[Al+3].[Y+3] JNDMLEXHDPKVFC-UHFFFAOYSA-N 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 229910019655 synthetic inorganic crystalline material Inorganic materials 0.000 description 1
- 229910019901 yttrium aluminum garnet Inorganic materials 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/67005—Apparatus not specifically provided for elsewhere
- H01L21/67011—Apparatus for manufacture or treatment
- H01L21/67144—Apparatus for mounting on conductive members, e.g. leadframes or conductors on insulating substrates
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the subgroups H01L21/06 - H01L21/326
- H01L21/4814—Conductive parts
- H01L21/4846—Leads on or in insulating or insulated substrates, e.g. metallisation
- H01L21/4853—Connection or disconnection of other leads to or from a metallisation, e.g. pins, wires, bumps
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
- H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
- H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
- H05K3/3457—Solder materials or compositions; Methods of application thereof
- H05K3/3478—Applying solder preforms; Transferring prefabricated solder patterns
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
- H05K2203/04—Soldering or other types of metallurgic bonding
- H05K2203/041—Solder preforms in the shape of solder balls
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
- H05K2203/04—Soldering or other types of metallurgic bonding
- H05K2203/043—Reflowing of solder coated conductors, not during connection of components, e.g. reflowing solder paste
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
- H05K2203/05—Patterning and lithography; Masks; Details of resist
- H05K2203/0548—Masks
- H05K2203/0557—Non-printed masks
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
- H05K2203/10—Using electric, magnetic and electromagnetic fields; Using laser light
- H05K2203/107—Using laser light
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
- H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
- H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
- H05K3/3494—Heating methods for reflowing of solder
Definitions
- the present invention relates to the use of soldering in the electrical connection between an IC device and a printed circuit board.
- the present invention relates to the use of laser technology for the ref lowing of solder balls on a ball grid array (BGA) device.
- BGA ball grid array
- BGA packaging of integrated circuit (IC) devices is gaining increasing importance in IC device production.
- the IC chip is commonly mounted on a copper substrate with pads, whereon flux is applied followed by the placement of solder balls. The solder balls are then soldered onto the pads in a reflow oven.
- the conventional method of ball placement is to use a vacuum suction head with the appropriate array of suction holes to pick up the soldering balls.
- the balls sucked up in the proper array onto the head are then lowered onto a substrate with pre-applied flux.
- This BGA assembly can then be conveyed to the reflow oven for soldering of the solder balls.
- the number of interconnecting pads per chip can be as high as 1 ,000 to 2,000, compared to a low density BGA package of below 400 pads per chip for the same surface area.
- the pitch (distance between two solder balls) and solder ball size have to be reduced accordingly.
- a low density BGA configuration of below 400 pads per chip with a pad diameter of 25 mil. and pitch of 50 mil. can use solder balls of 30 mil. diameter.
- solder balls of 12 mil. diameter have to be used instead.
- the first problem is placement problem. Due to the very small size and light weight of the solder balls, even a minute air turbulence or a minor warpage of the substrate might result in a displacement of the ball position. Because of the fine pitch required in high density arrays, even a slight displacement may result in bridging, which is the mixing of two soldering balls to form a connection during the process of soldering in a reflow oven. Once bridging occurs, the entire package has to be rejected. Consequently, conventional method of ball placement using the vacuum suction head results is high rejection rates due to bridging. The second problem is in the transfer of the packaging from the ball placement site to the reflow oven.
- the present invention is a system for solder ball placement and reflow on BGA packaging comprising means for template alignment, means for solder ball placement and a laser head.
- the template is aligned with connection pads located on the surface of the substrate with pre-applied flux.
- the aligned template allows accurate guiding of the balls onto the pads by the ball placement means.
- One ball is dropped into each hole in the template directly onto the pads containing a layer of flux.
- the solder balls positioned on the pads are then exposed to a laser via the laser head, resulting in the rapid melting of the solder balls directly onto the substrate pads.
- the melted balls are then allowed to cool rapidly.
- This laser reflow with template method eliminates the use of the reflow oven, which is a bulky equipment involved in the packaging of BGA devices, while increasing the accuracy of the ball placement and alleviates the problem of ball bridging.
- Figure 1 is a schematic illustration of the template-guided ball placement step according to the present invention.
- Figure 2 is a schematic illustration of the laser reflow step according to the present invention.
- Figure 3 is a schematic diagram to show the positioning of a laser head for laser reflow of the solder ball.
- Figure 4 is a flow diagram to illustrate the steps involved in the laser reflow process according to the present invention.
- the present invention utilizes a combination of two separate techniques to achieve synergistically superior results in the packaging of high density BGA devices.
- the first technique involves the use of a template to guide the release and placement of the ball from a conventional ball sucking head. Once the balls are properly placed above the substrate and within the template, the second technique of laser reflow is used, which causes the melting and effective soldering of the solder balls.
- the template can then be removed and the device transferred directly to the cleaner to remove the flux residue, eliminating the use of the bulky reflow oven, and also reducing the time required to complete the packaging process.
- Figure 1 shows a schematic illustration of the ball placement process according to the present invention.
- a template 22 of the high density array is placed over the substrate.
- a ball sucking head 24 with solder balls in position is aligned over substrate, using the template as a guide.
- the ball sucking head may be a conventional one commonly used in BGA packaging, with the array adapted for high density devices.
- the template can be a wire mesh with the mesh size of the required density.
- the template may be made from any material which is heat tolerant such as stainless steel and aluminum. A preferred material is stainless steel.
- the wire of the mesh should be thick enough to prevent a solder ball from rolling over the wire.
- the thickness of the wire of the mesh may be around 12 mil, to prevent the ball from rolling out of the cavity 27.
- the inner area of the cavity should preferably be slightly larger than the cross-sectional area of the solder ball for ease of placement by the ball sucking head, and prevention of a ball getting easily attached to the wire mesh.
- a preferred area is 15-
- Figure 2 illustrates how a matrix laser head is used to reflow the solder balls.
- the ball sucking head is moved away from the substrate after ball placement, and a laser head 30 is placed over the template and solder balls and melted rapidly under the laser beam to form intermetallic fusion. Once the laser beam is switched off, the molten solder ball cools rapidly at a high cooling rate.
- the laser head is preferably a gyroscope head or matrix type head comprising of a series of optical fibers arranged in an identical array as the ball array.
- Lasers such as neodymium.yttrium-aluminum-garnet (Nd.YAG) laser is suitable for laser reflow.
- the laser reflow may be performed under normal ambient conditions, or it can be performed in a nitrogen environment. The duration and intensity of the exposure varies with the different solder balls, and can be determined with routine experimentation.
- Figure 3 shows the alignment of the optic fibers of the laser head with the solder balls 28 placed inside the cavities 27 of the template 29 above the layer of flux 32.
- the optical fibers are housed in a housing 34 which fixes the array of the optical fibers 36 to match the array of the pads and the solder balls.
- the wire mesh of the template has a height 26 approximately the same as the diameter of the solder balls.
- Figure 4 is a flow diagram to show the process according to the present invention.
- the template is aligned with the substrate followed by ball placement with the ball sucking head 42.
- a visual check 44 is preferably performed to ensure that the balls are placed properly, followed by laser reflow 46.
- Steps 42-46 are preferably performed with the package stationary to minimize any disturbance to the balls once they are placed onto the substrate.
- the package may be heated in a reflow oven or a hot plate 48 for a short time to smoothen and polish the surfaces of the soldered balls.
- the visual checking step is preferably performed using a camera, for example a CCD (capacitor charge device) camera.
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Power Engineering (AREA)
- Ceramic Engineering (AREA)
- Electric Connection Of Electric Components To Printed Circuits (AREA)
Abstract
A system of laser reflow with template on BGA packaging comprising means for template alignment, means for solder ball placement and a laser head (36). The template (29) is aligned with connection pads located on the surface of the substrate with pre-applied flux. The aligned template allows accurate guiding of the balls (28) onto the pads by the ball placement means. One ball is dropped into each hole (27) in the template directly onto the pads containing a layer of flux. The solder balls positioned on the pads are then exposed to a laser via the laser head, resulting in the rapid melting of the solder balls directly onto the substrate pads. The melted balls are then allowed to cool rapidly. This laser reflow with template method eliminates the use of the reflow oven, which is a bulky equipment involved in the packaging of BGA devices, while increasing the accuracy of the ball placement and alleviates the problem of ball bridging.
Description
LASER REFLOW WITH TEMPLATE FOR SOLDER BALLS OF BGA
PACKAGING
FIELD OF THE INVENTION
The present invention relates to the use of soldering in the electrical connection between an IC device and a printed circuit board. In particular, the present invention relates to the use of laser technology for the ref lowing of solder balls on a ball grid array (BGA) device.
BACKGROUND OF THE INVENTION
Ball grid array (BGA) packaging of integrated circuit (IC) devices is gaining increasing importance in IC device production. In BGA packaging, the IC chip is commonly mounted on a copper substrate with pads, whereon flux is applied followed by the placement of solder balls. The solder balls are then soldered onto the pads in a reflow oven.
The conventional method of ball placement is to use a vacuum suction head with the appropriate array of suction holes to pick up the soldering balls. The balls sucked up in the proper array onto the head are then lowered onto a substrate with pre-applied flux. This BGA assembly can then be conveyed to the reflow oven for soldering of the solder balls.
Current trend in IC chip production is for greater IC density per chip. The higher the IC density, the greater the number of interconnects required on the same chip size. Therefore, there has been a demand for BGA packages with higher density pads and solder balls. In these high density BGA
packages, the number of interconnecting pads per chip can be as high as 1 ,000 to 2,000, compared to a low density BGA package of below 400 pads per chip for the same surface area. For high density packages above 400 pads per chip, the pitch (distance between two solder balls) and solder ball size have to be reduced accordingly. For example, a low density BGA configuration of below 400 pads per chip with a pad diameter of 25 mil. and pitch of 50 mil. can use solder balls of 30 mil. diameter. In the case of high density BGA configurations for example with pads diameter of 10 mil. and pitch of 20 mil., solder balls of 12 mil. diameter have to be used instead.
This reduced pitch and ball size poses a problem for the soldering process. The first problem is placement problem. Due to the very small size and light weight of the solder balls, even a minute air turbulence or a minor warpage of the substrate might result in a displacement of the ball position. Because of the fine pitch required in high density arrays, even a slight displacement may result in bridging, which is the mixing of two soldering balls to form a connection during the process of soldering in a reflow oven. Once bridging occurs, the entire package has to be rejected. Consequently, conventional method of ball placement using the vacuum suction head results is high rejection rates due to bridging. The second problem is in the transfer of the packaging from the ball placement site to the reflow oven. Even if the solder balls were placed accurately, the movement necessary to transfer the packaging to the reflow oven would cause the balls to be displaced. In addition to the problems stated above, the equipment for the various steps of ball placement and reflowing are bulky and expensive. There is therefore a need to improve the packaging process by designing new concepts of ball placement which would prevent displacement of the
solder balls and bridging while minimizing the amount of equipment involved in the process.
OBJECT OF THE INVENTION
It is an object of the present invention to provide an accurate method of solder ball placement in the packaging of BGA devices.
It is another object to reduce the occurrence of solder ball bridging in the reflowing process in BGA assembly line.
It is a further objective to eliminate the necessity of a reflow oven in the soldering of solder balls on BGA devices.
SUMMARY OF THE INVENTION
The present invention is a system for solder ball placement and reflow on BGA packaging comprising means for template alignment, means for solder ball placement and a laser head. The template is aligned with connection pads located on the surface of the substrate with pre-applied flux. The aligned template allows accurate guiding of the balls onto the pads by the ball placement means. One ball is dropped into each hole in the template directly onto the pads containing a layer of flux. The solder balls positioned on the pads are then exposed to a laser via the laser head, resulting in the rapid melting of the solder balls directly onto the substrate pads. The melted balls are then allowed to cool rapidly. This laser reflow with template method eliminates the use of the reflow oven, which is a bulky equipment involved in the packaging of BGA devices, while increasing the accuracy of the ball placement and alleviates the problem of ball bridging.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic illustration of the template-guided ball placement step according to the present invention.
Figure 2 is a schematic illustration of the laser reflow step according to the present invention.
Figure 3 is a schematic diagram to show the positioning of a laser head for laser reflow of the solder ball.
Figure 4 is a flow diagram to illustrate the steps involved in the laser reflow process according to the present invention.
DESCRIPTION OF THE INVENTION
The present invention utilizes a combination of two separate techniques to achieve synergistically superior results in the packaging of high density BGA devices. The first technique involves the use of a template to guide the release and placement of the ball from a conventional ball sucking head. Once the balls are properly placed above the substrate and within the template, the second technique of laser reflow is used, which causes the melting and effective soldering of the solder balls. The template can then be removed and the device transferred directly to the cleaner to remove the flux residue, eliminating the use of the bulky reflow oven, and also reducing the time required to complete the packaging process.
Figure 1 shows a schematic illustration of the ball placement process according to the present invention. After flux is applied to the substrate 20 according to conventional methods, a template 22 of the high density array is placed over the substrate. A ball sucking head 24 with solder balls in position is aligned over substrate, using the template as a guide. When the array in the ball sucking head is aligned with the array of the template, the vacuum on the ball sucking head is released, and the solder balls are discharged onto the substrate with flux. The ball sucking head may be a conventional one commonly used in BGA packaging, with the array adapted for high density devices. The template can be a wire mesh with the mesh size of the required density. The template may be made from any material which is heat tolerant such as stainless steel and aluminum. A preferred material is stainless steel. The wire of the mesh should be thick enough to prevent a solder ball from rolling over the wire. For example, for a solder ball
with diameter of 12 mil, the thickness of the wire of the mesh, as indicated by reference numeral 26 of Figure 3, may be around 12 mil, to prevent the ball from rolling out of the cavity 27. In addition, the inner area of the cavity should preferably be slightly larger than the cross-sectional area of the solder ball for ease of placement by the ball sucking head, and prevention of a ball getting easily attached to the wire mesh. A preferred area is 15-
35% larger than the cross-sectional area of the solder ball.
Figure 2 illustrates how a matrix laser head is used to reflow the solder balls. The ball sucking head is moved away from the substrate after ball placement, and a laser head 30 is placed over the template and solder balls and melted rapidly under the laser beam to form intermetallic fusion. Once the laser beam is switched off, the molten solder ball cools rapidly at a high cooling rate. The laser head is preferably a gyroscope head or matrix type head comprising of a series of optical fibers arranged in an identical array as the ball array. Lasers such as neodymium.yttrium-aluminum-garnet (Nd.YAG) laser is suitable for laser reflow. The laser reflow may be performed under normal ambient conditions, or it can be performed in a nitrogen environment. The duration and intensity of the exposure varies with the different solder balls, and can be determined with routine experimentation.
Figure 3 shows the alignment of the optic fibers of the laser head with the solder balls 28 placed inside the cavities 27 of the template 29 above the layer of flux 32. The optical fibers are housed in a housing 34 which fixes the array of the optical fibers 36 to match the array of the pads and the
solder balls. The wire mesh of the template has a height 26 approximately the same as the diameter of the solder balls.
Figure 4 is a flow diagram to show the process according to the present invention. After flux application 40, the template is aligned with the substrate followed by ball placement with the ball sucking head 42. After step 42, a visual check 44 is preferably performed to ensure that the balls are placed properly, followed by laser reflow 46. Steps 42-46 are preferably performed with the package stationary to minimize any disturbance to the balls once they are placed onto the substrate. After laser soldering, the package may be heated in a reflow oven or a hot plate 48 for a short time to smoothen and polish the surfaces of the soldered balls. The visual checking step is preferably performed using a camera, for example a CCD (capacitor charge device) camera.
While the present invention has been described particularly with references to Figs 1 and 4, it should be understood that the figures are for illustration only and should not be taken as limitation on the invention. It is contemplated that many changes and modifications may be made by one of ordinary skill in the art without departing from the spirit and the scope of the invention described.
Claims
1. A system of solder ball placement and laser reflow of ball grid array packaging of an IC chip with a substrate having an array of pads comprising :
means for template alignment
a template with an array of cavities matching said array of pads,
means for solder ball placement and
a laser module with a laser head adapted to send at least one laser beam onto said solder balls,
said system performing the sequential steps of :
aligning said cavities of said template with said array of pads having pre-applied flux;
aligning said means for solder ball placement with said substrate using said template as a guide so that an array of solder balls is aligned with said array of pads;
discharging said aligned solder balls onto said pads with pre-applied flux so that one solder ball is placed within each cavity of said template;
aligning said laser head with said substrate; and
discharging a laser beam onto said solder ball such that said solder balls are melted and soldered onto said pad.
2. A system for solder ball placement and laser reflow according to claim 1 wherein said system further comprises a camera, and an additional step of visual checking with said camera is performed after solder ball placement.
3. A system of solder ball placement and laser reflow of ball grid array packaging according to claim 1 wherein said laser head is a matrix laser head.
4. A system of solder ball placement and laser reflow of ball grid array packaging according to claim 1 wherein said laser head delivers a Nd.YAG laser beam.
5. A system of solder ball placement and laser reflow of ball grid array packaging according to claim 1 wherein said laser soldering step is performed under nitrogen environment.
6. A system for solder ball soldering placement and laser reflow according to any one of the preceeding claims wherein an additional step of heat polishing of said solder balls is performed with a reflow oven or a heat plate after said laser soldering step.
7. An apparatus for solder ball placement and laser reflow of ball grid array packaging of an IC chip with a substrate having an array of pads for interconnection comprising :
means for template alignment;
means for solder ball placement; and
a laser head adapted to send a laser beam onto said solder balls.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SG1997003590A SG67422A1 (en) | 1997-09-26 | 1997-09-26 | Laser reflow with template for solder balls of bga packaging |
SG9703590-1 | 1997-09-26 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1999017594A1 true WO1999017594A1 (en) | 1999-04-08 |
Family
ID=20429747
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/SG1998/000055 WO1999017594A1 (en) | 1997-09-26 | 1998-07-06 | Laser reflow with template for solder balls of bga packaging |
Country Status (3)
Country | Link |
---|---|
SG (1) | SG67422A1 (en) |
TW (1) | TW380290B (en) |
WO (1) | WO1999017594A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2003003444A2 (en) * | 2001-06-26 | 2003-01-09 | Pac Tech - Packaging Technologies Gmbh | Method for producing a substrate arrangement |
-
1997
- 1997-09-26 SG SG1997003590A patent/SG67422A1/en unknown
-
1998
- 1998-04-30 TW TW087106695A patent/TW380290B/en active
- 1998-07-06 WO PCT/SG1998/000055 patent/WO1999017594A1/en active Application Filing
Non-Patent Citations (5)
Title |
---|
1ST 1997 IEMT/IMC SYMPOSIUM, (IEEE Cat. No. 97CH36056), Published Tokyo, Japan 1997, "High Density BGA Substrates Fabricated by Laser Technology", HIRAKAWA T. et al., pages 295-298. * |
DERWENT ABSTRACT, Accession No. 96-281730/29, Class L03, M23; & JP 08118005 A (MATSUSHITA DENKI SANGYO KK) 14 May 1996. * |
PROCEEDINGS OF THE TECHNICAL PROGRAM, NATIONAL ELECTRONIC PACKAGING AND PRODUCTION CONFERENCE, NEPCON EAST 1994, Published STAMFORD, CT, USA, "An Overview of Advancements in Surface Mount and Fine Pitch Technology", RUA R., pages 336-343. * |
RECENT PROGRESS IN PRINTED CIRCUIT BOARD TECHNOLOGY, Berlin, Germany, 27-29 January 1997, "Solder Ball Bumping for Printed Circuit Boards", KASULKE P. et al., page 176. * |
SOLID STATE TECHNOLOGY, Volume 39, No. 9, PENNWELL PUBLISHING USA, September 1996, "Laser Drilling Speeds BGA Packaging", LIZOTTE T. et al., pages 120-122, 124, 127, 128. * |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2003003444A2 (en) * | 2001-06-26 | 2003-01-09 | Pac Tech - Packaging Technologies Gmbh | Method for producing a substrate arrangement |
WO2003003444A3 (en) * | 2001-06-26 | 2003-07-31 | Pac Tech Gmbh | Method for producing a substrate arrangement |
US6955943B2 (en) | 2001-06-26 | 2005-10-18 | Pac Tech-Packaging Technologies Gmbh | Method for producing a substrate arrangement |
GB2382224B (en) * | 2001-06-26 | 2006-02-22 | Pac Tech Gmbh | Method for producing a substrate arrangement |
Also Published As
Publication number | Publication date |
---|---|
TW380290B (en) | 2000-01-21 |
SG67422A1 (en) | 1999-09-21 |
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