Application Notes

AN106920
Handling and processing of sawn wafers on UV dicing tape
Rev. 2.0 — 13 January 2009
Application note
Document information
Info
Content
Keywords
Sawn wafers, UV dicing tape, handling and processing
Abstract
This application note gives hints and recommendations regarding correct
handling and processing of sawn wafers mounted on irradiated UV dicing
tape. The recommendations are based on NXP internal assembly
experience and must be seen as guideline only. In addition to processing
recommendations this document presents the results of various tests
which have been performed by NXP in order to ensure damage-free
shipment of the delivery type “sawn wafer on FFC with irradiated UV
dicing tape”.
AN106920
NXP Semiconductors
Sawn wafers on UV dicing tape
Revision history
Rev
Date
Description
2.0
2009-01-13
• Section 2.3.1: recommendation regarding LASER diced wafers added
• Chapter 3 updated: drop test results with LASER diced wafers added; typo
regarding Lintec foil type corrected
• Document transferred to corporate NXP template
1.0
2005-02-11
Initial version
Contact information
For additional information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]
© NXP B.V. 2006. All rights reserved.
Application note
Rev. 2.0 — 13 January 2009
2 of 9
AN106920
NXP Semiconductors
Sawn wafers on UV dicing tape
1. Introduction
This application note gives hints and recommendations regarding correct handling and
processing of sawn wafers mounted on irradiated UV dicing tape according the “General
Specification for 8” Wafer on UV-tape”. The processing recommendations are based on
NXP internal assembly experience and must be seen as guideline only. Process fine
tuning and optimization remains in the full responsibility of the customer.
In addition to processing recommendations this document presents the results of various
tests which have been performed by NXP in order to ensure damage- and yield loss-free
shipment of the delivery type “sawn wafer on FFC with irradiated UV dicing tape”.
© NXP B.V. 2006. All rights reserved.
Application note
Rev. 2.0 — 13 January 2009
3 of 9
AN106920
NXP Semiconductors
Sawn wafers on UV dicing tape
2. Handling and processing recommendations
2.1 Differences between irradiated UV dicing tape and conventional tape
The adhesion strength between irradiated UV dicing tape and silicon is approximately
three times lower compared to non UV dicing tape (i.e. “sticky tape” or “blue tape”).
Furthermore irradiated UV dicing tape almost completely loses its adhesion strength to
the silicon in case excessive shear forces are applied to the adhesive layer. This leads to
the following important differences for the pick and place process of sawn wafers on
irradiated UV dicing tape compared to conventional blue tape:
•
No or only minimum spreading of the tape is advised at the pick and place process.
This prevents loose dies prior to pick and place.
•
Adjustment of the mechanical pick parameters (e.g. push up needle geometry,
push up forces and profile) is advised in order to reflect the lower adhesion force of
the irradiated UV dicing tape properly.
2.2 General recommendations
•
Optimization of the assembly process in general (equipment adaption and accurate
process parameter setting) by final product manufacturer is recommended in order
to prevent mechanical stress and damage of the ICs.
•
Ultrasonic cleaning is not permitted.
•
ESD safe working environment and equipment is advised.
2.3 Conventional assembly
2.3.1 Die Attach
•
Cleaning of wafer surface by gentle N2 blow before push up is advised.
•
No or minimum spreading of sawn wafer on FFC is advised. In case of LASER
diced wafers it should additionally be ensured that the working area of the pick &
place equipment is made large enough to comply with the increased wafer
diameter due to die separation spreading.
•
Any backside damage due to improper push up needle(s), force and profile has to
be avoided.
•
Even distribution of adhesive under the die is advised (100% of die area should be
covered with adhesive).
•
Adhesive type: conductive or non-conductive.
•
Adhesive thickness: min. 10 µm (standard epoxy material).
2.3.2 Wire Bonding
•
Preferable process:
–
thermosonic bonding (Au wire)
•
No chip out under bond pad metallization is allowed.
•
No bond closer than 2 µm to the adjacent passivation layer at the edge of the
bondpad.
© NXP B.V. 2006. All rights reserved.
Application note
Rev. 2.0 — 13 January 2009
4 of 9
AN106920
NXP Semiconductors
Sawn wafers on UV dicing tape
2.4 Flip chip assembly
2.4.1 Pick and place
•
Cleaning of wafer surface by gentle N2 blow before push up is advised.
•
No or minimum spreading of sawn wafer on FFC is advised.
•
Any backside damage due to improper push up needle(s), force and profile has to
be avoided.
2.4.2 Direct chip attach assembly (DCA)
Bumped dies offered by NXP Semiconductors can be assembled by flip chip processes
using ACF (anisotropic conductive film), ACP (anisotropic conductive paste), nonconductive and conductive glues. Other compatible DCA processes are TCB (thermo
compression bonding) and direct conductive paste printing.
© NXP B.V. 2006. All rights reserved.
Application note
Rev. 2.0 — 13 January 2009
5 of 9
AN106920
NXP Semiconductors
Sawn wafers on UV dicing tape
3. Packing and shipping
3.1 Conventionally diced parts (blade dicing)
3.1.1 Shipping test program
The use of the specified packing method 3322 845 08351 for customer shipment of sawn
wafers on irradiated UV dicing tape has been released based on the results of the
following tests and field experience:
1. Test sequences : standard drop and vibration tests according UN-D 1400.
a. 3 axis vibration test (frequency 7 Hz, amplitude 5.3 mm, acceleration 1.05 g,
30 min. each axis) + drop test program 1 (7 drops, 1 m drop height).
b. 3 axis vibration test + drop test program 1 + 2 hours vibration test (most critical
axis).
c.
3 axis vibration test + drop test program 1 + 2 × 2 hours vibration test (most
critical axis).
2. Shipment trial of all sample material used in item 1. from Hamburg to Bangkok and
back.
3. Field experience from more than 30000 sawn wafers on irradiated UV dicing tape
shipped to customers and NXP production sites.
3.1.2 Results
3.1.2.1 Standard drop and vibration tests
The results from the standard drop and vibration test sequences are shown in Table 1.
Table 1.
Missing/delaminated dies vs. total dies
Die size: 1 mm2
Die size: 0.5 mm2
Adwill D-175
Nitto UE-111AJ
Adwill D-175
Nitto UE-111AJ
Test sequence a.
5/31k
3/31k
3/62k
0/62k
Test sequence b.
0/31k
0/31k
1/62k
0/62k
Test sequence c.
13/31k
10/31k
24/124k
3/124k
3.1.2.2 Shipment trial with drop test material
No additional missing or delaminated dies were observed.
3.1.2.3 Field experience
To date no complaints regarding missing or delaminated dies due to shipment received.
3.2 Laser diced parts
3.2.1 Shipping test program
Test sequences : standard drop and vibration tests according UN-D 1400.
a. 3 axis vibration test (frequency 7 Hz, amplitude 5.3 mm, acceleration 1.05 g, 30
min. each axis)
b. Drop test program 1 (7 drops, 1 m drop height)
© NXP B.V. 2006. All rights reserved.
Application note
Rev. 2.0 — 13 January 2009
6 of 9
AN106920
NXP Semiconductors
Sawn wafers on UV dicing tape
3.2.2 Results
Table 2.
Missing/delaminated dies vs. total dies
Die size: 0.3 mm2
Nitto UE-111AJ
Wafer 1
Wafer 2
Test sequence a.
0/99k
0/99k
Test sequence b.
0/99k
60/99k
3.3 Conclusion
In case excessive vibration and/or dropping is applied to the packed material few dies
may delaminate from the irradiated UV dicing tape. Under normal shipping conditions,
however, no delamination was ever seen on more than 30000 shipped wafers. Therefore
the risk for yield loss due to wafer shipping can be considered extremely low for sawn
wafers on irradiated UV dicing tape.
© NXP B.V. 2006. All rights reserved.
Application note
Rev. 2.0 — 13 January 2009
7 of 9
AN106920
NXP Semiconductors
Sawn wafers on UV dicing tape
4. Legal information
4.1 Definitions
Draft — The document is a draft version only. The content is still under
internal review and subject to formal approval, which may result in
modifications or additions. NXP Semiconductors does not give any
representations or warranties as to the accuracy or completeness of
information included herein and shall have no liability for the consequences
of use of such information.
4.2 Disclaimers
General — Information in this document is believed to be accurate and
reliable. However, NXP Semiconductors does not give any representations
or warranties, expressed or implied, as to the accuracy or completeness of
such information and shall have no liability for the consequences of use of
such information.
Suitability for use — NXP Semiconductors products are not designed,
authorized or warranted to be suitable for use in medical, military, aircraft,
space or life support equipment, nor in applications where failure or
malfunction of a NXP Semiconductors product can reasonably be expected
to result in personal injury, death or severe property or environmental
damage. NXP Semiconductors accepts no liability for inclusion and/or use of
NXP Semiconductors products in such equipment or applications and
therefore such inclusion and/or use is for the customer’s own risk.
Applications — Applications that are described herein for any of these
products are for illustrative purposes only. NXP Semiconductors makes no
representation or warranty that such applications will be suitable for the
specified use without further testing or modification.
Right to make changes — NXP Semiconductors reserves the right to make
changes to information published in this document, including without
limitation specifications and product descriptions, at any time and without
notice. This document supersedes and replaces all information supplied prior
to the publication hereof.
© NXP B.V. 2006. All rights reserved.
Application note
Rev. 2.0 — 13 January 2009
8 of 9
AN106920
NXP Semiconductors
Sawn wafers on UV dicing tape
5. Contents
1.
2.
2.1
Introduction .........................................................3
Handling and processing recommendations....4
Differences between irradiated UV dicing tape
and conventional tape ........................................4
2.2
General recommendations .................................4
2.3
Conventional assembly ......................................4
2.3.1
Die Attach...........................................................4
2.3.2
Wire Bonding......................................................4
2.4
Flip chip assembly..............................................5
2.4.1
Pick and place....................................................5
2.4.2
Direct chip attach assembly (DCA) ....................5
3.
Packing and shipping .........................................6
3.1
Conventionally diced parts (blade dicing)...........6
3.1.1
Shipping test program ........................................6
3.1.2
Results ...............................................................6
3.1.2.1
Standard drop and vibration tests ......................6
3.1.2.2
Shipment trial with drop test material .................6
3.1.2.3
Field experience.................................................6
3.2
Laser diced parts................................................6
3.2.1
Shipping test program ........................................6
3.2.2
Results ...............................................................7
3.3
Conclusion .........................................................7
4.
Legal information ................................................8
4.1
Definitions ..........................................................8
4.2
Disclaimers.........................................................8
5.
Contents...............................................................9
Please be aware that important notices concerning this document and the product(s)
described herein, have been included in the section 'Legal information'.
© NXP B.V. 2006. All rights reserved.
For more information, please visit: http://www.nxp.com
For sales office addresses, email to: [email protected]
Date of release: 13 January 2009
Document identifier:
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