Increasing the bonding strength of chips on flex substrates using thermosonic flip-chip bonding process with nonconductive paste

Chuang, Cheng-Li; Liao, Qing-An; Li, Hsun-Tien; Liao, Shi-Jie; Huang, Guo‐Shing

doi:10.1016/j.mee.2009.08.027

Cited by 20 publications

(3 citation statements)

References 4 publications

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“…Flip-chip bonding has been extensively used on flexible substrates in several variations, including reflow soldering and thermocompression processes for thin dice (50 μm) (Banda et al 2008;Zhang et al 2009), but dispensing the underfill without allowing the material to flow on top of the very thin die is challenging. Polymeric adhesives are also very popular for flip-chip bonding on flexible substrates (Lai and Liu 1999;Chen et al 2000;Lu and Chen 2010;Chiang et al 2006;Chuang et al 2010) as they can eliminate the need for underfill. The adhesive acts as the interconnection medium between the bumped chip and the substrate, while it at the same time protects the contacts and provides mechanical support.…”

Section: Asic Assemblymentioning

confidence: 99%

Realizing flexible bioelectronic medicines for accessing the peripheral nerves – technology considerations

Giagka

Serdijn

2018

Bioelectron Med

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Section: Asic Assemblymentioning

confidence: 99%

Realizing flexible bioelectronic medicines for accessing the peripheral nerves – technology considerations

Giagka

Serdijn

2018

Bioelectron Med

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“…Usually, at this stage, some specific material needs to be applied at the bonding interface between the flexible paper substrate and the component to be bonded, to assist the mechanical and electrical performance reliability. For this purpose, a wide range of options are available, between isotropic or anisotropic conductive (ACP) and non-conductive adhesives (NCP), as either paste or film [22][23][24][25]. The issue with the use of this complementary bonding technique and assistive materials is the need to add an extra step and extra material in the roll-to-roll (R2R) or sheet-tosheet (S2S) assembling process line, possibly increasing cost and reducing throughput.…”

Section: Introductionmentioning

confidence: 99%

Direct flip-chip bonding of bare dies to polypropylene-coated paper substrates without adhesives or solders

Rodrigues

Weissbach

Malik

et al. 2022

J Mater Sci: Mater Electron

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Paper-based electronics is an emerging concept with the prospect of developing recyclable, low cost, flexible, and green products such as paper displays, smart labels, RFID tags, smart packages, electronic magazines, biological and medical devices. Compared to conventional printed circuit board (PCB) materials, utilizing paper as an electronics substrate has both physical and chemical challenges. Nowadays, the integration of components on papers are mainly conducted using adhesives [such as anisotropic conductive paste (ACP), isotropic conductive paste (ICP), and non-conductive pastes (NCP)] or low-temperature solders. The application of adhesives and solders in a roll-to-roll fabrication line of papers requires an additional dispensing or printing unit, which has its own drawbacks. Therefore, alternative approaches such as pre-applied adhesive films either on bare dies or papers can gain significant attention. In this study, by exploiting the unique properties of a paper coating material (i.e., polypropylene) as a non-conductive adhesive, it was shown that direct flip-chip bonding of the bare dies and devices could be successfully performed on paper without using any additional adhesives or solders. The electrical and mechanical performance of the flip chip-bonded dies on the polypropylene-coated paper substrate were assessed utilizing daisy-chain contact resistance measurement and die-shear analysis, respectively. Moreover, for an RFID tag application, RFID chips were flip chip bonded to the coated papers and functional tests via NFC communication were also successfully exerted. It was concluded that the polypropylene film on the paper can be considered as an intrinsic NCP layer for flip-chip integration of bare dies.

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“…For example, it has been carried out to bond Al/Cu-Cu in wire bonding [16][17][18] and Au-Ag/Cu/Al in flip chip bonding. [19][20][21][22] The application of ultrasonic vibration to the bonding interface can enhance the deformation of metal wires, balls or bumps, which results in the exposure of a fresh surface to a counter electrode material and, therefore, reduces the bonding temperature. [23][24][25] However, there have been few reports on room-temperature Cu-Cu bonding in flip-chip technology.…”

Section: Introductionmentioning

confidence: 99%

Room-Temperature Cu Microjoining with Ultrasonic Bonding of Cone-Shaped Bump

Qiu

Ikeda

Noda³

et al. 2013

Jpn. J. Appl. Phys.

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Room-temperature Cu–Cu bonding was realized by applying ultrasonic vibration together with compression force to the bonding of a cone-shaped bump. The size of the bump was about 10 µm. The connection pitch was 20 µm. Mechanical characterization showed that the bonding strength increases with vibration amplitude and depends on the thickness of the counter electrode made of Cu. The thickness dependence of the bonding strength was found to be caused by an increase in the surface roughness of the counter electrode. It was shown that the bonding strength meets the requirement from application to products. Electrical characterization using a daisy-chain connection test demonstrated that more than 10,000 pins on a chip can be connected with a sufficiently low resistance.

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Increasing the bonding strength of chips on flex substrates using thermosonic flip-chip bonding process with nonconductive paste

Cited by 20 publications

References 4 publications

Realizing flexible bioelectronic medicines for accessing the peripheral nerves – technology considerations

Realizing flexible bioelectronic medicines for accessing the peripheral nerves – technology considerations

Direct flip-chip bonding of bare dies to polypropylene-coated paper substrates without adhesives or solders

Room-Temperature Cu Microjoining with Ultrasonic Bonding of Cone-Shaped Bump

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