有延遲時間的MOCVD製程反應腔體內部壓力控制系統的強健控制

Abstract

LED因具有耗電量小、元件壽命較長等優點，因此近年來LED被普遍應用在手機、汽機車燈源以及各種顯示屏幕上，目前業界在生產LED元件上，大多是使用金屬有機物化學氣相沉積(Metal Organic Chemical Vapor Deposition, MOCVD)氮化鎵(GaN)薄膜於藍寶石基板上。 然而目前多數MOCVD反應腔內壓力的控制，是使用PID控制器，它在控制非線性、時間延遲及參數和系統存在不確定性的複雜 製程時，性能表現不如預期。 因此本論文使用系統鑑別，鑑別出系統模型，並開發出離散Robust DOB控制架構，以補償含時間延遲之真空壓力控制機制，使其具有處理時間延遲及系統不穩定性之控制能力，達成更精準之真空壓力控制，進而提升薄膜品質。

Light Emitting Diode (LED) was extensively used in recent years due to its low power consumption and long-life time. In the LED-related industries, the Metal Organic Chemical Vapor Deposition (MOCVD) is in common used for deposition GaN films on sapphire substrate. However, most chamber pressure system exist dead-time, nonlinearity and model uncertainty. In order to obtain a better process quality, in this thesis, we use system identific--ation (ID) to approach a suitable process model of chamber pressure system in MOCVD process, and applied Discrete Time Robust DOB controller with Dead-time compensation.