Rate-Dependent Adhesion Between a Spherical PDMS Stamp and Silicon Substrate for a Transfer-Assembly Process

Jang, Beom‐Su; Kim, Kwang‐Seop; Kim, Jae Hyun; Choi, Hyun-Ju; Park, Hyunsung; Lee, Hak‐Joo

doi:10.1080/00218464.2011.597302

Cited by 13 publications

(9 citation statements)

References 14 publications

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“…This indicated that the adhesion strength of the thin elastomeric layer could be readily tuned by adjusting the confinement ratio and the separation velocity. When the separation velocity was 2 μm/s, the energy release rate was 314 mJ/m 2 , which is comparable to values reported for bulk samples. , …”

Section: Resultssupporting

confidence: 83%

“…The compliance and contact area change according to the contact geometry of the contacting materials. For the contact geometry between a spherical lens and a flat, thin elastomeric layer, the compliance of the layer can be determined as a function of the confinement ratio ( a c / t ) according to eq : where E is the elastic modulus of the elastomeric layer and has a value of 2 MPa for PDMS . The relationship between the compliance and the ratio a c / t in eq shows that an increase in a c / t reduces the compliance of the layer, which means that the effective stiffness of the layer increases due to the confinement effect.…”

Section: Resultsmentioning

confidence: 99%

“…where E is the elastic modulus of the elastomeric layer and has a value of 2 MPa for PDMS. 11 The relationship between the compliance and the ratio a c /t in eq 2 shows that an increase in a c /t reduces the compliance of the layer, which means that the effective stiffness of the layer increases due to the confinement effect. When the compliance of eq 1 is substituted with eq 2, the normalized pull-off force (F pull-off /a c 3/2…”

Section: Acs Applied Materials and Interfacesmentioning

confidence: 99%

“…When the separation velocity was 2 μm/s, the energy release rate was 314 mJ/m 2 , which is comparable to values reported for bulk samples. 11,27 Knowing the rate-dependent characteristics and the confinement effect of the thin elastomeric layer, a stamp with a thin elastomeric layer could be designed by considering the adhesion properties of the target substrate. To verify the design process of the stamp, we evaluated the adhesion strength of a target flexible substrate and demonstrated the reversible transfer of Si chips onto the flexible substrate using the designed stamp.…”

Section: Acs Applied Materials and Interfacesmentioning

confidence: 99%

“…Various techniques such as surface treatments, use of the rate-dependent characteristic of elastomers, and surface patterning have been suggested to control the adhesiveness of a stamp. − Chemical surface treatments such as plasma and ultraviolet (UV) treatments are typically used due to their simplicity and compatibility for large-area treatments. , However, the adhesion of a stamp is irreversibly modified by such treatments, rendering them unusable for repeated picking and placing . One way to reversibly control adhesion is to use the viscoelastic response of an elastomeric stamp, i.e., its rate-dependent adhesion. − The adhesion energy could be much larger than the thermodynamic work of adhesion at high separation velocity because the energy dissipation due to viscoelastic loss increases with the separation velocity . When pulling the stamp away from the device at a sufficiently high separation velocity, the adhesion between the stamp and device is strong enough to detach the device from the donor substrate.…”

Section: Introductionmentioning

confidence: 99%

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Ultimate Control of Rate-Dependent Adhesion for Reversible Transfer Process via a Thin Elastomeric Layer

Kim

Yoon

Jang

et al. 2017

ACS Appl. Mater. Interfaces

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Adhesion between a stamp with an elastomeric layer and various devices or substrates is crucial to successfully fabricate flexible electronics using a transfer process. Although various transfer processes using stamps with different adhesion strengths have been suggested, the controllable range of adhesion is still limited to a narrow range. To precisely transfer devices onto selected substrates, however, the difference in adhesion between the picking and placing processes should be large enough to achieve a high yield. Herein, we report a simple way to extend the controllable adhesion range of stamps, which can be achieved by adjusting the thickness of the elastomeric layer and the separation velocity. The adhesion strength increased with decreasing layer thickness on the stamp due to a magnification of the confinement and rate-dependent effects on the adhesion. This enabled the controllable range of the adhesion strength for a 15 μm-thick elastomeric layer to be extended up to 12 times that of the bulk under the same separation conditions. The strategy of designing stamps using simple adhesion tests is also introduced, and the reversible transfer of thin Si chips was successfully demonstrated. Tuning and optimizing the adhesion strength of a stamp according to the design process suggested here can be applied to various materials for the selective transfer and replacement of individual devices.

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Section: Resultssupporting

confidence: 83%

Section: Resultsmentioning

confidence: 99%

Section: Acs Applied Materials and Interfacesmentioning

confidence: 99%

Section: Acs Applied Materials and Interfacesmentioning

confidence: 99%