Low Temperature Fine Pitch All-Copper Interconnects Combining Photopatternable Underfill Films

Conference Paper (2023)
Authors

Xinrui Ji (TU Delft - Microelectronics, TU Delft - Electronic Components, Technology and Materials)

Henk van Zeijl (TU Delft - Microelectronics, TU Delft - Electronic Components, Technology and Materials)

Weiping Jiao (Student TU Delft)

S. He (TU Delft - Materials and Environment)

Leiming Du (TU Delft - Electronic Components, Technology and Materials, TU Delft - Microelectronics)

Guo Qi Zhang (TU Delft - Microelectronics, TU Delft - Electronic Components, Technology and Materials)

Research Group
Electronic Components, Technology and Materials
Copyright
© 2023 X. Ji, H.W. van Zeijl, Weiping Jiao, S. He, L. Du, Kouchi Zhang
To reference this document use:
https://doi.org/10.1109/ECTC51909.2023.00211
More Info
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Publication Year
2023
Language
English
Copyright
© 2023 X. Ji, H.W. van Zeijl, Weiping Jiao, S. He, L. Du, Kouchi Zhang
Research Group
Electronic Components, Technology and Materials
Bibliographical Note
Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public. @en
Pages (from-to)
1237-1243
ISBN (electronic)
9798350334982
DOI:
https://doi.org/10.1109/ECTC51909.2023.00211
Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Abstract

The trend to 3D and heterogeneous integration enable driving multi-functional blocks in one package. Flip-chip integration is currently playing an important role and is based on solder joints. To overcome the limitations of solder joints, all-copper interconnects have been investigated to meet electrical, thermal, and reliability demands in 3D integration. The underfill process is widely applied in flip-chip encapsulation technology. We propose a novel wafer-scale all-Cu interconnect method combining epoxy-based photo-patternable polymer as self-aligned underfill layer with the patterned copper nanoparticles interconnects. The resulting test wafers were able to pattern 20 µm pitch copper nanoparticle-paste interconnects on both substrates with and without photoimageable polymer. The Cu paste was applied to form the interconnects and was sintered after bonding process. Free-standing nanocopper is sintered to obtain mechanical properties with a Young's modulus of 112 GPa. All-Cu interconnects with diameter of 50 µm and 100 µm were measured to achieve the specific contact resistance, ranging from 1.4 × 10-5O· cm2 to 1.0 × 10-5O· cm2 at different sintering temperature when epoxy-based underfill existing. And its resistivity was 4.54× 10-4 O· cm, compared to 5.86× 10-4O· cn for the all-Cu interconnects without underfill.

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