29.1: A Real‐time On‐line Illumination and Light Decline Monitoring Technology

Abstract

Mask plays major role in the photolithography process during whole TFT manufacturing. The photolithography process transfers the desired pattern on mask into panel substrate, which forms some portions of device and performs some electric or optical functions. Due to pattern continuously duplicated, a correct pattern shape of mask is very important in the photolithography process. An abnormal pattern will results in huge loss of yield and cost.The haze, a foreign matter grown or deposited on the surface of mask, is already a prevalent phenomenon in TFT photolithography manufacturing or well known in semiconductor manufacturing. It is already well identified that it is highly related to the storage environment of mask, that is, the so called AMC (Airborne Molecular Contamination).A summarized mask haze classification based on past industrial service experience is proposed and a case study result with haze sampling at the site of mask manufacturer is followed in this review to show the understanding of the recently state of the art about mask haze in TFT industry.With the development of industrial technology, the clean room area of TFT panel and semiconductor plant construction project is getting larger and larger (a single clean area of 100,000 square meters), and the investment cost is getting higher and higher. The owners have higher and higher requirements on the cost control and intelligence of the project, including plant construction cost, operating cost and energy saving, which have been highly concerned by the owners. In the actual execution of TFT panels and semiconductor projects, owners often hear the problems about clean room lighting system, which are summarized as follows: The illumination required by the process is 400lux, and the initial design is 600lux. By artificially opening the number of lamps, the attenuation problem of the light source for a long time in the later period is compensated. The owner needs to close several circuits of lamps in the early stage to meet the illuminance requirements of the clean room. If the lamps and lanterns are not closed in the early stage, part of the operation cost and energy waste will be caused; With the passage of time, the illumination of clean room will also decrease with time, and when to what illumination should be opened several circuit lamps, in order to meet the needs of clean room process? But also not waste energy and so on; With the operation of the plant, when can the illumination of the clean room lamps and lanterns not meet the requirements of the process when they are all opened? And when do light fixtures need to be replaced? Part of the lamps are broken. Whether the illuminance of the clean room in this area is much lux, and whether it meets the illuminance demand of the process, etc.; In the illuminance test when the project is completed and handed over to the owner, it is usually done by outsourcing or management personnel at different points to measure manually on the spot, which consumes time and labor cost, and if the instrument measurement is wrong, the amount of newly measured works is relatively huge, etc. When do clean room lamps need to be replaced? The owner will normally deal with the above problems: If more experienced owners turn on or off the number of lamps and lanterns based on their experience, there are also risks of energy waste and insufficient illumination; All open to meet the illuminance demand, there is excessive waste of energy and operation costs; With the passage of time, light source attenuation, part of the lamps are broken, usually artificial field measurement, to confirm whether the lamps need to be replaced, time and labor costs; If the process department doubts the illuminance value of the factory department, it also needs to measure on site or find the data of the completed illuminance test before as the basis, especially the existing clean room renovation project; The measurement of completion acceptance is usually on‐site measurement or outsourcing can provide corresponding data to prove acceptance, etc.; According to the above problems, this paper describes a real‐ time online illuminance and light decline monitoring technology to deal with the actual problems of TFT panel and semiconductor. Automatic control is realized for the closing and opening of the owner's lamps through the cumulative average illuminance, etc., and the requirements of the process illuminance are met to save energy consumption and operating costs; The real‐time cumulative monitoring of the luminescence life curve of this technology is compared with the luminescence life curve provided or tested by the manufacturer, which can confirm the early warning and comparison of the deviation between the actual luminescence life and the luminescence life provided by the manufacturer, so that the owners can purchase or replace the number and area of the luminescence in advance;