Patent ID: 8264812

Claim:
A method for bonding a first substrate and a second substrate, comprising the steps of: applying different voltages to five groups of electrostatic blocks constituting an upper electrostatic chuck, respectively, thereby chucking the first substrate to the upper electrostatic chuck; applying different voltages to five groups of electrostatic blocks constituting a lower electrostatic chuck, respectively, thereby chucking the second substrate, which has been dispensed with a liquid crystal material, to the lower electrostatic chuck; lowering the first substrate adhered to the upper electrostatic chuck toward the second substrate with a distance between about 500 to 800 μm and performing a first alignment; further lowering the first substrate adhered to the upper electrostatic chuck toward the second substrate with a distance between about 100 to 250 μm and performing a second alignment; uniformly dropping the first substrate from the upper electrostatic chuck at the distance between about 100 to 250 μm toward the second substrate by individually controlling the five different voltages applied to the upper electrostatic chuck to enhance the uniformity of the release of the chucked substrate, after performing the second alignment and before bonding the first and second substrates; and bonding the first and second substrates respectively chucked to the upper and lower electrostatic chucks, wherein the five groups of electrostatic blocks comprise: a first electrostatic block having sub-blocks arranged at corner portions of the electrostatic chuck having a quadrilateral shape, wherein a first voltage is applied to the first electrostatic block; a second electrostatic block, having a 2×4 matrix of sub-blocks, arranged at a central portion of the electrostatic chuck having the quadrilateral shape, wherein a second voltage different from the first voltage is applied to the second electrostatic block; third electrostatic blocks, each having two adjacent sub-blocks, arranged at upper and lower edge portions of the electrostatic chuck having the quadrilateral shape, wherein a third voltage different from the first and second voltages is applied to the third electrostatic blocks; a fourth electrostatic block, having four adjacent sub-blocks, arranged at a left edge portion of the electrostatic chuck having the quadrilateral shape, wherein a fourth voltage different from the first, second and third voltages is applied to the fourth electrostatic block; and a fifth electrostatic block, having four adjacent sub-blocks, arranged at a right edge portion of the electrostatic chuck having the quadrilateral shape, wherein a fifth voltage different from the first, the second, the third, and the fourth voltages is applied to the fifth electrostatic block.