Planarization Technologies and Fidelity Evaluation Systems of the Next Generation Color Filter for LCD

• Main Authors: Tan-Ching Yen, 顏丹青
• Other Authors: Pei-Lum Tso
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/02928930625527644633

博士 === 國立清華大學 === 動力機械工程學系 === 94 === An effective process for fabricating color filters (CF) must satisfy three requirements: 1. low-cost material, 2. simple procedures, and 3. high throughput. Several systemic issues affect the conventional CF process, such as the pigment-dispersion method. For high yield and low cost, it is necessary to develop a new fabrication method for CFs, which are not affected by these systemic issues. In this paper, an entirely new process for fabricating CFs is introduced. This process, which satisfies the three requirements above, introduces chemical-mechanical polishing techniques to produce CFs for LCDs. Because of the usage of chemical-mechanical polishing techniques, this new CF fabrication method is named the color filter polishing (CFP) method. Based on the high resolution and high aperture ratio needed for LCD (Liquid Crystal Display), we introduced the advanced color filter polishing technology for processing a fine line-width BM (Black Matrix) of a color filter. The dimensional compensation method for the pattern-size design of the photo-mask according to the characteristics of the colorant resists was described to rectify the line-width variation caused by the proximity aligner, the most popular exposure machine in the color filter manufacturing. In this paper, we introduce the color filter polishing and the photo-mask compensation technologies into the present color filter process flows and equipments to achieve the need for a fine line-width BM to increase the aperture ratio of LCD and to accomplish a real color filter sample with 5.8�慆 line-width BM. For portable digital displays, the pattern of a color filter should resemble the design pattern as much as possible to avoid contrast loss within the liquid crystal display (LCD). The higher the quality requirement of a LCD is, the smaller the difference between the design pattern and the actual pattern of a color filter, also known as “pattern fidelity,” should be. In this work, we use the histogram of the different segments between the designed pattern and the actual pattern to define the critical shape error (CSE) indices, CSEavg, CSE90, and CSE80, the area percentage indices of the “white zone” (W.Z. Area %) and the “over zone” (O.Z. Area %), and the maximum segment width of the “over zone” (Max. CSE width). Through the evaluation of all indices of the optical proximity correction (OPC) patterns, we choose the optimal OPC pattern, the hexagon OPC pattern circumscribing a circle of diameter in 3�慆, and have a color filter with very good pattern fidelity.