|
Abstract
The washing cost of the TFT-LCD physical vapor deposition mask has traditionally accounts for the majority of total unit cost. Therefore, methods to prolong the lifespan of the mask and reducing the washing cost are the main objectives of the company in planning and controlling the internal cost. In this study, the first aluminum-making process of the physical vapor deposition is used to conduct the latter stage of the physical back-coating process as required by the mask. Since the mask is able to absorb excessive Aluminum atoms, the mask needs to be frequently replaced after the mask adsorbs Aluminum atoms to a certain degree (the end of Life). For this reason, we altered the structure and style of the mask in addition to carry out product testing through statistical hypothesis, in order to prove the feasibility of the experiment thereby achieving the objective of prolonging the lifespan of the mask as well as effectively reducing the washing cost. First, we collected the mask life of various experiments and used the life hours (in kwh) to record and sort data. Then we chose one out of the four Aluminum-making process equipments as the testing machine, which we used to conduct horizontal spreading test after it has been satisfactory tested, in order to test the effect of the various apparatus on prolonging the life of the mask as well as looking into how different types of mask differ in prolonging the life of the mask. Furthermore, we used the statistical software Minitab to verify the product yield rate before and after the mask were brought in (which includes the array yield, array zero bright spot rate, cell lighting yield, cell zero bright spot rate and the ratio of eighty-eight customers) as well as checking whether the defect product sheet has any effect or not. Finally, it was found out, through the results of both mask testing and software testing, that there was a significant improvement when the length of the aluminum bar was increased. The result of this experiment suggests that it is possible to increase the mask life from the original 4000kwh to 10000kwh without causing any problems to the device. Thus, not only did the objective of prolonging the lifespan of the mask been achieved but we also effectively reduce the washing cost, as we can save about 25% in the cost of washing the mask per month, in addition to having the financial benefits of saving nearly 600 million per year.
|