| Popis: |
A centrifugal coating technology was researched to coating the uniform thickness photoresist on a concave spherical surface.Firstly,the critical factors affecting the uniform of photosensitive resist and the film forming force were investigated.Then,the centrifugal glue adhesive force during the flow state was analysed in the spherical photoresist spin coating down opening based on the hydrodynamic theory.A mathematical model to describe the relationship among the film thickness and centrifuge speed,viscosity of photoresist and the spin coating time was derived.Finally,in order to verify the correctness of the formula,some experiments of photoresist spin coating on the K9 glass concave sphere with a diameter of 120 mm,radius of 300 mm,vector height of 12.5 mm were performed.The experimental results certify that the proposed theory is consistent with the actual situation well.On the theoretical analysis,the uniform film thickness on the inner surface of an entire sphere can be obtained with the disalignment of photoresis pin coating axis and the main axis of electric engine.When the viscosity of photoresist is 1.1~1.9 Pa and the speed of main axis is 3 000-6 000/r·min-1,the uniform film thickness is 0.5~1 μm on a concave sphere. |
