fluxless laser solder jetting for optoelectronics and mems ... · author name, company name,...
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Author name, Company name, Program name - Slide 1
Fluxless Laser Solder Jetting for Optoelectronics and MEMS Packaging
Thorsten Teutsch*, Elke Zakel, Ronald G. Blankenhorn*Pac Tech – Packaging Technologies GmbH
Am Schlangenhorst 15 -17, Germany
Phone: + 49 (0) 33 21/ 44 95 - 0Fax: + 49 (0) 33 21/ 44 95 - 23
email: [email protected]: www.pactech.de
*Pac Tech – Packaging Technologies USA, Inc.328 Martin Avenue, Santa Clara, CA 95050, USA
Phone: + 1 408 588 – 1925x2Fax: + 1 408 588 – 1927
Mobile: + 1 408-421-7465email: [email protected]
URL: www.pactech-usa.com
Abstract
The packaging of optoelectronics and MEMS devices is placing challenging requirements for the interconnection and soldering technology. These requirements can no longer be met with standard flux–based processes which use a long temperature reflowprofile and are implementing a lot of mechanical handling steps and processes. Basically, the packaging of these new devices is requiring fluxless soldering, no thermal stress by localized heating, low respectively no mechanical contact and damage on sensitive membranes in MEMS or optical components (like lenses, etc.). Some of these applications even require 3D–packaging and selective solder application in 3D-structures, like cavity, vertical assembly, etc. An additional, very challenging requirement is a high flexibility in solder alloys because eutectic tin lead and other lead-based solder alloys are not applicable. Instead Gold/Tin and Indium-based solder alloys are required.
In order to fulfill the specific needs in these applications, a new laser-based solder jetting technology has been developed. This technology fulfills all the needs of fluxless soldering, local heating and reflow, no mechanical contact and stress during soldering, high solder alloy flexibility and capability of 3D-packaging. Prior to developing the Solder Ball Bumper Jet (SB²-Jet) process, many potential applications have been elaborated using the Solder Ball Bumping (SB²)-technology. The advantage of SB²-Jet is basically the higher throughput which the jet process. With a throughput of 10 balls/s, it fulfills most of the requirements for today’s packaging of optoelectronics and MEMS devices in production. A further increase in speed to 20 and 30 balls/s is in progress for the next generation. An additional feature of the SB²- and SB²-Jet-technology is the repair option and repair capability. This permits individual removal and replacement of solder balls and solder contacts and allows to increase the yield and productivity of cost-intensive high end devices.
Author name, Company name, Program name - Slide 2
Fluxless Laser Solder Jetting for Optoelectronic and MEMS Packaging
E. Zakel, L. Titerle, T. Teutsch*, R. G. Blankenhorn*PacTech GmbH, Nauen/D, *PacTech Inc, Santa
Clara/USPhone:+ 49 - 3321 4495 –0
+ 1 - 408-588 [email protected], [email protected]
www.pactech.de
SEMICON Europa 2003International MEMS/MST Industry Forum
March 31, 2003
Author name, Company name, Program name - Slide 3
Content
• Introduction• Overview
- Solder Ball Bumping Laser Soldering Process- Solder Ball Bumping Laser Soldering Equipment- Solder Ball Bumping Advantages- Solder Ball Bumping Applications- Solder Ball Bumping Reliability
• Summary
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• Explanation:
• What stands SB² for ?
SB² = Solder Ball Bumping
New Process => SB²- Jet
Process
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SB²-SM Process (standard)
Placement & Reflow of Solder Balls
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SB²-Jet Process (new)
Pad-Metalization
Solder Ball
Substrate
SB²-Jet Tool
Solder Mask
LaserNitrogen
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Advantages• No tooling• Solder ball diameters from 80µm to 760µm• Solder alloys: (SnPb, SnAg, SnAgCu, AuSn)• No flux• No mechanical stress/contact• No thermal stress• No aditional reflow• No cleaning of flux residues
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ApplicationsFast prototyping & production for:• Wafer bumping• BGA/CSP, WLCSP• Optoelectronic components• MEMS packaging• HDD• 3-D packaging
Rework/Repair of• BGA/CSP
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Applications
Solder Ball Placement on RF modules
LTCC
BGA
IC
n Mobile Phone, 0,9 - 1,9 GHz
n Bluetooth, 2,4 GHz
n Distance Radar, 70 GHz
Bluetooth module on LTCC substrate
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Applications
200µm Sn63Pb37 on top of 300µm Sn10Pb90
Solder Ball Placement on a Flex CSP
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Optoelectronic Substrate
Fluxfree Solder Bumping using SB²-Jet
232 SB2
Applications
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Fluxless Bumping of HGA‘s for HDD
50 SB2
Applications
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CSP Reballing
228 SB2
µBGA
300 µm Solder Ball diameter
Applications
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Reliability
Area configuration of solder bumps
Solder Ball Placement on Wafer Level
Cross section of eutetic SnPb bump
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Optimal Solder Wetability
Metallographic Cross Sections
231 SB2
Reliability
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Reliability
Cross section of an HDD Flex Suspension
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CSP Ball placement using SB2
Shear mode: 100% Ball shear with optimal laser parameters
57 SB2
Reliability
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Shear Test
230 SB2
Shear Force: min. 300 g
(Solder Ball diameter: 300µm)
Reliability
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Cpk: 2,33 Solder Ball diameter: 300µm
Solder Alloy – Eutectic SnPb 63/37
Fracture Mode: Solder Shear
233 SB2
SB² Reliability Shear Test Data
200220
240260280
300320340
360380400
420440
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
No. of sheared balls
shea
rfo
rce/
gra
mm
Average Shearforce, 368g, standard dev. = 16,8 g
Reliability
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after Reflow and Flux-Cleaning
Shearmode: solder/solder
Shearforce:
Mean: 96,75 gSigma: 5,24 g
Sample size: 20Pad size: 100 µm
Lead-free Solder Bumping, SnAgCu
33 BUMP
Reliability
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CSP Ball placement using SB2
shear force / bumpversus laser powersolder ball diameter: 300µm
250
270
290
310
330
350
370
390
39 40 41 42 43 44 45 46 47 48 49
Laser Power [A]
Sh
ea
r F
orc
e /
Bu
mp
[c
N]
5 ms
7 ms
10 ms
59 SB2
Reliability
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0
1
2
3
4
5
6
7
8
9
10
0 200 400 600 800 1000 1200 1400 1600
Time [h]
Con
tact
Res
ista
nce
[mΩ
]
Contact Resistance [mOhm]
Storage temperature 150 °C
199
Reliability
FC on FR4 after Thermal Storage