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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

Fabrication of the mask for SU-8 selective polymerization by depositing Al thin film only inside the microchannel.Glass flat slide (a), deposition of positive resist over this slide and then pre-bake (b), UV exposure, development producing the mask for microchannel pattern transfer, and hard bake (c), glass etching (d), deposition of opaque thin film by sputtering over all of the slide (e), and lift-off with the thin film only inside the etched cavity (f). Features not drawn to scale.
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f4: Fabrication of the mask for SU-8 selective polymerization by depositing Al thin film only inside the microchannel.Glass flat slide (a), deposition of positive resist over this slide and then pre-bake (b), UV exposure, development producing the mask for microchannel pattern transfer, and hard bake (c), glass etching (d), deposition of opaque thin film by sputtering over all of the slide (e), and lift-off with the thin film only inside the etched cavity (f). Features not drawn to scale.

Mentions: As explained earlier in “General Considerations” section, the mask for selective cure of adhesive resist was based on the deposition of a film of Al inside the microchannel. Al is ideal because it is cheaper than other metals like Au and is easily removed in HF or alkaline diluted solutions—a required step after SU-8 development. Vapour phase deposition methods are potential alternatives taking into account their high production capacity and film uniformity. The protocol applied in this specific process is depicted in Fig. 4. The resist for engraving the microchannel and the ATZs was retained after etching of the glass slides. Next, Al thin film was deposited via sputtering (Oerlikon Balzers BA510, Schaumburg, IL). Lastly, acetone excess lifted off the etching mask for 2 min. As a consequence, a selective coating of the cavities by Al was attained. The developed method avoids both alignment and further photolithography steps applied in standard processes for pattern transfer of the microchannel and ATZs by wet etching.


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)

Fabrication of the mask for SU-8 selective polymerization by depositing Al thin film only inside the microchannel.Glass flat slide (a), deposition of positive resist over this slide and then pre-bake (b), UV exposure, development producing the mask for microchannel pattern transfer, and hard bake (c), glass etching (d), deposition of opaque thin film by sputtering over all of the slide (e), and lift-off with the thin film only inside the etched cavity (f). Features not drawn to scale.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f4: Fabrication of the mask for SU-8 selective polymerization by depositing Al thin film only inside the microchannel.Glass flat slide (a), deposition of positive resist over this slide and then pre-bake (b), UV exposure, development producing the mask for microchannel pattern transfer, and hard bake (c), glass etching (d), deposition of opaque thin film by sputtering over all of the slide (e), and lift-off with the thin film only inside the etched cavity (f). Features not drawn to scale.
Mentions: As explained earlier in “General Considerations” section, the mask for selective cure of adhesive resist was based on the deposition of a film of Al inside the microchannel. Al is ideal because it is cheaper than other metals like Au and is easily removed in HF or alkaline diluted solutions—a required step after SU-8 development. Vapour phase deposition methods are potential alternatives taking into account their high production capacity and film uniformity. The protocol applied in this specific process is depicted in Fig. 4. The resist for engraving the microchannel and the ATZs was retained after etching of the glass slides. Next, Al thin film was deposited via sputtering (Oerlikon Balzers BA510, Schaumburg, IL). Lastly, acetone excess lifted off the etching mask for 2 min. As a consequence, a selective coating of the cavities by Al was attained. The developed method avoids both alignment and further photolithography steps applied in standard processes for pattern transfer of the microchannel and ATZs by wet etching.

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