scholarly journals High–Thick Thermal Reflow Process Using Vacuum-assisted Micromolding for Submillimeter Microvalves

2021 ◽  
Vol 33 (12) ◽  
pp. 4441
Author(s):  
Takaaki Abe ◽  
Shunya Okamoto ◽  
Yoshiaki Ukita
Keyword(s):  
Reflow Process ◽  
Thermal Reflow

An Investigation on the Profile of Microlens by the Thermal Reflow Process Due to Surface Tension and Gravity

2008 ◽  
Author(s):  
Jhy-Cherng Tsai ◽  
Yong-Sung Hsu
Keyword(s):  
Surface Tension ◽  
Critical Radius ◽  
Critical Size ◽  
Liquid Droplet ◽  
Bond Number ◽  
Diameter Ratio ◽  
Experimental Result ◽  
Critical Number ◽  
Reflow Process ◽  
Thermal Reflow

Microlens and its mold fabricated by thermal reflow using photoresist have been widely used for forming patterns in different scales. When the photoresist solidifies from melting condition, for example by the reflow process, its profile is formed based on the balance between surface tension and gravity. This research is aimed to investigate the influence of surface tension and gravity on the profile of microlens in thermal reflow process. Theoretical analysis based on the interaction between surface tension and gravity of liquid droplet is first investigated. The result showed that the height to diameter ratio (h/D), or the sag ratio, of the liquid droplet is affected by the Bond number (Bo), a number defined as the ratio of gravity to surface tension. The sag ratio is not sensitive to Bo when Bo is small but the ratio decreases as Bo increases if Bo is over the critical number. Based on the analysis, the critical number for the AZ4620 photoresist on a silicon substrate is 1, corresponding to the critical radius of droplet R = 2,500μm. When the size of the droplet is less then the critical size, the profile is mainly controlled by the surface tension and thus the sag ratio is about the same regardless the size. The profile, in contrast, is highly affected by the gravity if the size of the droplet is larger then the critical size. The sag ratio decreases exponentially with respect to Bo in this case. Experiments are also designed and conducted to verify the analysis. Experimental result showed that the sag ratio of the photoresist reduces to 0.065 from 0.095 when Bo increases from 0.0048 to 0.192. The results showed that the trend is consistent to the theoretical model.

Tilted Microlens Fabrication Using Nano-Magnetic Particles

2015 ◽  
Vol 1105 ◽  
pp. 259-263
Author(s):  
Shih Yu Hung ◽  
Yu Ting Hung ◽  
Ming Ho Shen
Keyword(s):  
Magnetic Field ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Magnetic Particles ◽  
Lower Layer ◽  
Glassy State ◽  
Reflow Process ◽  
Photoresist Layer ◽  
Thermal Reflow

Double-layer heterogeneous photoresist method will be used firstly to obtain the round photoresist column with two layers of different photoresists. Since both photoresists are the positive-type, the exposure is only required once. During the thermal reflow processing, the upper photoresist layer (AZ-4620 and nanomagnetic powder mixture) reaches the glass transition temperature, which is transformed from a glassy state into a rubbery state. Since the glass transition temperature of the lower photoresist layer (AZ-5214E) is higher than the temperature of thermal reflow, the lower photoresist layer is still able to maintain its solid state. The lower layer creates a round base during the thermal reflow process, and then subjected to an appropriate magnetic field. The base can not only restrict the bottom shape of the liquid photoresist to a round shape but also prevent the sliding of liquid photoresist during the thermal reflow process, so the tilted microlens array can be obtained. We can vary the strength of magnetic field to control the oblique angle of the tilted microlens.

Polymer elastic bump formation through photodefinable thermal reflow process for system in foil package

2018 ◽  
Vol 28 (11) ◽  
pp. 115008
Author(s):  
Chung Woo Lee ◽  
Jae Hak Lee ◽  
Jun Yeob Song ◽  
Seung Man Kim ◽  
Yong Jin Kim ◽  
...  
Keyword(s):  
Reflow Process ◽  
Thermal Reflow

Analysis of Thermal Reflow Process for Polymer Microlens Fabrication

2018 ◽  
Vol 35 (3) ◽  
pp. 319-325 ◽  
Author(s):  
Ji Hoon Lee ◽  
Sang Hyuk Yum ◽  
Seung Mo Kim
Keyword(s):  
Reflow Process ◽  
Thermal Reflow

Exploration of lift-off Ge–As–Se chalcogenide waveguides with thermal reflow process

2019 ◽  
Vol 92 ◽  
pp. 206-211 ◽  
Author(s):  
Yang Zhao ◽  
Chengdong Li ◽  
Panpan Guo ◽  
Wei Zhang ◽  
Peipeng Xu ◽  
...  
Keyword(s):  
Reflow Process ◽  
Lift Off ◽  
Thermal Reflow

High fill-factor microlens array mold insert fabrication using a thermal reflow process

2004 ◽  
Vol 14 (8) ◽  
pp. 1197-1204 ◽  
Author(s):  
Hsiharng Yang ◽  
Ching-Kong Chao ◽  
Mau-Kuo Wei ◽  
Che-Ping Lin
Keyword(s):  
Fill Factor ◽  
Mold Insert ◽  
Microlens Array ◽  
Reflow Process ◽  
High Fill Factor ◽  
Thermal Reflow

scholarly journals Large-area fabrication of microlens arrays by using self-pinning effects during the thermal reflow process

2019 ◽  
Vol 27 (3) ◽  
pp. 3439 ◽  
Author(s):  
S. G. Heo ◽  
D. Jang ◽  
H.-J. Koo ◽  
H. Yoon
Keyword(s):  
Reflow Process ◽  
Large Area ◽  
Microlens Arrays ◽  
Thermal Reflow

A new fabrication method for an asymmetric microlens array light control film using inclined exposure and an incomplete thermal reflow process

2014 ◽  
Vol 38 (1) ◽  
pp. 85-92 ◽  
Author(s):  
Tsung-Hung Lin ◽  
Shih-Yu Hung ◽  
Chien-Hsin Hung ◽  
Ming-Ho Shen ◽  
Ching-Kong Chao ◽  
...  
Keyword(s):  
Microlens Array ◽  
Fabrication Method ◽  
Light Control ◽  
Reflow Process ◽  
Control Film ◽  
Thermal Reflow

scholarly journals A surface micromachined optical scanner array using photoresist lenses fabricated by a thermal reflow process

2003 ◽  
Vol 21 (7) ◽  
pp. 1700-1708 ◽  
Author(s):  
H. Toshiyoshi ◽  
Guo-Dung John Su ◽  
J. LaCosse ◽  
M.C. Wu
Keyword(s):  
Reflow Process ◽  
Optical Scanner ◽  
Thermal Reflow
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