Plasma assisted method of accurate alignment and pre-bonding for microstructure including glass or quartz chip
The plasma-assisted method of precise alignment and pre-bonding for microstructure of glass and quartz microchip belongs to micromachining and bonding technologies of the microchip. The steps of which are as follows: photoresist and chromium layers on glass or quartz microchip are completely removed followed by sufficient cleaning of the surface with nonionic surfactant and quantities of ultra-pure water. Then the surface treatment is proceeded for an equipping surface with high hydrophily with the usage of plasma cleaning device. Under the drying condition, the precise alignment is accomplished through moving substrate and cover plate after being washed with the help of microscope observation. Further on, to achieve precise alignment and pre-bonding of the microstructure of glass and quartz microchip, a minute quantity of ultrapure water is instilled into a limbic crevice for adhesion, and entire water is completely wiped out by vacuum drying following sufficient squeezing. Based on the steps above, it is available to achieve permanent bonding by further adopting thermal bonding method. In summary, it takes within 30 min to finish the whole operation of precise alignment and pre-bonding by this method. Besides, this method is of great promise because of its speediness, efficiency, easy maneuverability, operational safety and wide applications.
1. A plasma-assisted method of accurate alignment and pre-bonding for a microstructure including a glass or quartz chip, the method comprising sequential steps of:
a) removing superficial photoresist and chromium layers of substrate and cover plates of glass or quartz microchips after wet etching;
b) washing the substrate and cover plates using a detergent and then water to remove superficial organics, solid particles, and dust;
c) blowing majority of the water away from the substrate and cover plates and then performing a rinse and activation using a plasma cleaning device to make the substrate and cover plates to be hydrophily;
d) obtaining the rinsed and activated subtract and cover plates and then sticking the rinsed and activated subtract and cover plates, thereby performing a preliminary alignment; wherein the performing the preliminary alignment comprises performing the preliminary alignment using naked eyes;
e) performing an accurate alignment on the rinsed and activated subtract and cover plates under a drying condition and then placing water into an edge of a gap between the subtract and cover plates to form a hydrophilic layer between surfaces of the subtract and cover plates and to make the subtract and cover plates stick tightly to each other; wherein the performing the accurate alignment comprises performing the accurate alignment under a microscope;
f) removing extra water from the subtract and cover plates by pressing the subtract and cover plates and then blowing water away from the edge; and
g) removing remaining water from the subtract and cover plates by vacuuming using the plasma cleaning device to obtain pre-bonded glass or quartz chips.
2. The method of claim 1 , wherein materials of the substrate plates in step a) comprise glass or quartz materials.
3. The method of claim 1 , wherein the performing the rinse and activation in step c) comprises performing the rinse and activation for 3-10 minutes and gas for stimulating plasma of the plasma cleaning device comprises air, nitrogen or oxygen.
4. The method of claim 1 , wherein the placing the water into the edge of the gap comprises placing water on the edge of the gap using 2-7 μL water such that the water enters the gap via capillary penetration after the performing the accurate alignment in step e).
5. The method of claim 1 , wherein the blowing the water away comprises blowing the water away using a high-pressure air gun.
6. The method of claim 1 , wherein the vacuuming using the plasma cleaning device in step g) comprises vacuuming for 5-20 minutes using the plasma cleaning device.
7. The method of claim 6 , wherein the accurate alignment and pre-bonding are performed within 20-35 minutes.
8. The method of claim 6 , Further comprising: performing a thermal bonding method on the pre-bonded glass or quartz chips by placing the pre-bonded glass or quartz chips into a muffle furnace and heating the pre-bonded glass or quartz chips based on a predetermined heating procedure to obtain permanent bonded glass or quartz chips.
9. The method of claim 8 , wherein a rate of the predetermined heating procedure is 1-3° C. per minute, an initial temperature of the predetermined heating procedure is a room temperature, the maximum temperature of the predetermined heating procedure is 550° C.-1200° C., a temperature holding time of the predetermined heating procedure is 1-3 hours, a cooling rate of the predetermined heating procedure is 0.5-5.5° C. per minute, and a final temperature of the predetermined heating procedure is the room temperature.