| Summary: | 碩士 === 國立交通大學 === 工學院半導體材料與製程設備學程 === 103 === Abstract
Various types of touch sensors have evolved to be manufactured in a production mode starting from a small trail production to the mass production due to swift changes in the competitive cell phone industry as it can shorten the lead time of production. The applied materials are assigned according to customers’ requirement for circuits thus a factory needs to have a quick response to customers’ needs. Even when the customers ask the factory to become the second supplier, the factory needs to use the “first supplier’s “material to undertake production. Hence, some materials are not certified onsite and the trail production starts off quickly and goes on with mass production. The production schedule will be decided according to the market feedback and sales performance of products. If the sales performance is not satisfactory, the orders would be cut off and the mass production would be forced to cease. Therefore a timely response to production procedure and better yield rate are becoming the key issues to tackle.
Surface Capacitive single layer multi-touch sensor is a new design with different production paths and materials as to distinguish out from the old style. The experienced engineer would set up the production parameters during production to retrieve the tolerance range of each parameter. 8D and PCDA approaches are applied to adjust and improve the production situation and results. When the second stage production starts, the production parameters are generated using Analysis of variance (referred to as ANOVA hereunder) to attain the result of each parameter’s influence on the production and interaction effects.
The production parameters of single layer multi-touch sensor include: dimension of models, resistance value result after anealing, critical dimension after photo etching on the ITO pattern, the thickness of isolation rubber for screen printing, accuracy of models dimension, alignment accuracy of screen printing silver circuit location and thickness, and critical dimension of silver circuits. In order to obtain the immediate and correct production parameters, every production process needs to be systematized and digitized. The variance data obtained by the experiment design can compute the optimal parameter combination of production in order to avoid the risk of instability and inaccuracy caused by the traditional calculation. The most optimal production parameters obtained by variation analyses in this project are as follows:
Aging (ITO baking time 45 min, temperature of 160 ℃), dry film exposure (energy32 mj), development (time 45 min, temperature of 160 ℃), silver screen printing (squeegee pressure: 25 kgf, squeegee speed :100 mm / s ,height from screen to work stage: 3.0 mm), insulating rubber screen printing (squeegee pressure 35 kgf, squeegee speed of 80 mm / s, height from screen to work stage: 3.0 mm).
The production parameters obtained by data analysis can be applied to shorten the testing time and to reduce defect factors largely caused by trial and error methods. The analysis models established by ANOVA can be used for material production of ITO film, insulation rubber and silver paste etc. as to avoid failure of material production, improve defect-free rate, stabilize the product quality and speed up the production schedule.
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