The Improvement Magnet Plate on a Reticle Stage of Lithography Equipment through Analyzing Adhesive and Roughness of Plate

Semiconductor lithography scanners are extremely complex equipment which is used to manufacture IC(Intergrated Circuit). Moore's law, which states that the computing power per chip doubles every one and a half to two years, has consistently held for four decades. [1] The exposure system in semiconductor has been rapidly developed based on the Moore's law. Most semiconductor manufacturers have been using ASML scanner for exposure on wafers. The reticle stage of ASML scanner exists over magnet plates. The electric currents are supplied to the coil of the inside magnet，the reticle stage can move forward and backward by Fleming's left hand rule. [3] The reticle stage is synchronized with wafer stage of movement. At that time, scan speed is very fast, reticle stage scan velocity is about 2.4m/sec, in addition acceleration reaches to 9G. So the conditions are very harsh to stage. However, with current technology, we cannot manufacture the whole mass of magnet as long as long stroke of reticle stage. (approximately 2.4m) So they manufacture it on plate by attaching 600mm pieces of magnet. Over time, the magnet plates attached to the main frame are getting weak. At the end of magnet which is the weakest point can be easily cracked because it is changing of flux density in magnet plate. We analyze bonding method between magnet and plate. In addition, we tested it on a different roughness for the plate. Through the change of the material and roughness, we could improve prevent the plate from cracking. In this paper, we propose how to protect broken magnet by changing the material of adhesive and roughness of plate. As a result, we can expect to increase stability in the magnet plate on a reticle stage by more than 10%.

 

[1] G. E. Moore, “Cramming more components onto integrated circuits,” Electron. Mag., vol. 38, no. 8, pp. 4–7, 1965.

[2] Hans Butler, “Position control in lithographic equipment”, IEEE Control Systems Magazine, October 2011

[3] Kenjō, Takashi, and Shigenobu Nagamori. Permanent-magnet and brushless DC motors. Vol. 18. Oxford University Press, USA, 1985.