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Sacrificial adhesive bonding: a powerful method for fabrication of glass microchips.

Lima RS, Leão PA, Piazzetta MH, Monteiro AM, Shiroma LY, Gobbi AL, Carrilho E - Sci Rep (2015)

Bottom Line: This step relies on a selective development to remove the SU-8 only inside the microchannel, generating glass-like surface properties as demonstrated by specific tests.Finally, the SAB protocol is an improvement on SU-8-based bondings described in the literature.Aspects such as substrate/resist adherence, formation of bubbles, and thermal stress were effectively solved by using simple and inexpensive alternatives.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Microfabricação, Laboratório Nacional de Nanotecnologia, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, São Paulo 13083-970, Brazil.

ABSTRACT
A new protocol for fabrication of glass microchips is addressed in this research paper. Initially, the method involves the use of an uncured SU-8 intermediate to seal two glass slides irreversibly as in conventional adhesive bonding-based approaches. Subsequently, an additional step removes the adhesive layer from the channels. This step relies on a selective development to remove the SU-8 only inside the microchannel, generating glass-like surface properties as demonstrated by specific tests. Named sacrificial adhesive layer (SAB), the protocol meets the requirements of an ideal microfabrication technique such as throughput, relatively low cost, feasibility for ultra large-scale integration (ULSI), and high adhesion strength, supporting pressures on the order of 5 MPa. Furthermore, SAB eliminates the use of high temperature, pressure, or potential, enabling the deposition of thin films for electrical or electrochemical experiments. Finally, the SAB protocol is an improvement on SU-8-based bondings described in the literature. Aspects such as substrate/resist adherence, formation of bubbles, and thermal stress were effectively solved by using simple and inexpensive alternatives.

No MeSH data available.


Related in: MedlinePlus

Testing the adhesion strength.This graphic shows the pressures inside the channel arising from flow rates applied by an HPLC pump. The chips were bonded with SU-8 adhesive in different processing stages: (1) post pre-bake (uncured, grey), (2) post-UV exposure (with produced cure initiator but uncured, yellow), and (3) post PEB (cured, red).
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f7: Testing the adhesion strength.This graphic shows the pressures inside the channel arising from flow rates applied by an HPLC pump. The chips were bonded with SU-8 adhesive in different processing stages: (1) post pre-bake (uncured, grey), (2) post-UV exposure (with produced cure initiator but uncured, yellow), and (3) post PEB (cured, red).

Mentions: The results for the leakage tests and adhesion strength are presented in Fig. 7. Microfluidic channels did not show any leakage for any of the applied flow rates. However, the connections between the pump and the microchips leaked over 800 μL min−1 for both SU-8 adhesives obtained post UV exposure and PEB and over 1,200 μL min−1 for the resist attained post pre-bake. Consequently, sudden reductions in pressure were observed. Taking up the tested flow rates (previously to the leaks in connections), the microchips endured pressures of up to 3.9 MPa. In addition, we can state that the preliminary bonding presented an adhesion strength high enough to withstand the pressures applied during the selective development step (flow rate lower than 100 μL min−1).


Sacrificial adhesive bonding: a powerful method for fabrication of glass microchips.

Lima RS, Leão PA, Piazzetta MH, Monteiro AM, Shiroma LY, Gobbi AL, Carrilho E - Sci Rep (2015)

Testing the adhesion strength.This graphic shows the pressures inside the channel arising from flow rates applied by an HPLC pump. The chips were bonded with SU-8 adhesive in different processing stages: (1) post pre-bake (uncured, grey), (2) post-UV exposure (with produced cure initiator but uncured, yellow), and (3) post PEB (cured, red).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4543966&req=5

f7: Testing the adhesion strength.This graphic shows the pressures inside the channel arising from flow rates applied by an HPLC pump. The chips were bonded with SU-8 adhesive in different processing stages: (1) post pre-bake (uncured, grey), (2) post-UV exposure (with produced cure initiator but uncured, yellow), and (3) post PEB (cured, red).
Mentions: The results for the leakage tests and adhesion strength are presented in Fig. 7. Microfluidic channels did not show any leakage for any of the applied flow rates. However, the connections between the pump and the microchips leaked over 800 μL min−1 for both SU-8 adhesives obtained post UV exposure and PEB and over 1,200 μL min−1 for the resist attained post pre-bake. Consequently, sudden reductions in pressure were observed. Taking up the tested flow rates (previously to the leaks in connections), the microchips endured pressures of up to 3.9 MPa. In addition, we can state that the preliminary bonding presented an adhesion strength high enough to withstand the pressures applied during the selective development step (flow rate lower than 100 μL min−1).

Bottom Line: This step relies on a selective development to remove the SU-8 only inside the microchannel, generating glass-like surface properties as demonstrated by specific tests.Finally, the SAB protocol is an improvement on SU-8-based bondings described in the literature.Aspects such as substrate/resist adherence, formation of bubbles, and thermal stress were effectively solved by using simple and inexpensive alternatives.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Microfabricação, Laboratório Nacional de Nanotecnologia, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, São Paulo 13083-970, Brazil.

ABSTRACT
A new protocol for fabrication of glass microchips is addressed in this research paper. Initially, the method involves the use of an uncured SU-8 intermediate to seal two glass slides irreversibly as in conventional adhesive bonding-based approaches. Subsequently, an additional step removes the adhesive layer from the channels. This step relies on a selective development to remove the SU-8 only inside the microchannel, generating glass-like surface properties as demonstrated by specific tests. Named sacrificial adhesive layer (SAB), the protocol meets the requirements of an ideal microfabrication technique such as throughput, relatively low cost, feasibility for ultra large-scale integration (ULSI), and high adhesion strength, supporting pressures on the order of 5 MPa. Furthermore, SAB eliminates the use of high temperature, pressure, or potential, enabling the deposition of thin films for electrical or electrochemical experiments. Finally, the SAB protocol is an improvement on SU-8-based bondings described in the literature. Aspects such as substrate/resist adherence, formation of bubbles, and thermal stress were effectively solved by using simple and inexpensive alternatives.

No MeSH data available.


Related in: MedlinePlus