LED磊晶製程設備內旋轉效應對於熱流場影響之改進研究

Abstract

目前LED晶粒製造中主要的磊晶技術乃採用有機金屬化學氣相沉積 (Metal-Organic Chemical Vapor Deposition, MOCVD)，這項技術已被廣泛應用在製作高亮度LED、太陽能電池薄膜、以及其他光電元件上。影響磊晶過程的主要因素有：反應室幾何形狀、反應壓力、進氣構造、以及反應氣體流量等，以上因素均影響反應腔體中的流場性質以及基板溫度分佈，和磊晶品質有高度相關性。 一般磊晶反應均在基板高速旋轉下進行，而此旋轉效應將使熱流現象更為複雜。為進一步了解反應室內之流場分佈，本計畫預計使用粒子影像測速儀(Particle Image Velocimetry, PIV)來做流場觀察及測量；設計不同之進氣機構(圓孔式、長槽式、複合式)，研究其在反應腔體內的流場均勻性；同時改良進氣(上方進氣、斜角進氣、下方進氣)以及排氣方式、以減少擾流之發生；研究不同進氣流量、基板加熱溫度、以及轉速下，旋轉基板上之熱浮力效應和重要實驗參數對流體穩定度之影響。 本計畫希望藉由以上的研究，了解受旋轉效應而造成的流場變化，改善有機金屬化學氣相沉積平台內之流場性質，藉以增進磊晶之均勻性以及品質，進而提升國人自製LED磊晶設備之技術水準。

Metal Organic Chemical Vapor Deposition (MOCVD) has been widely applied to the manufacturing of high brightness LED, thin film solar cells, and other optoelectronic components. Several factors affect the epitaxial process, including geometry of the reactor chamber, reaction pressure, inlet flow flange design, and gas flow rate. The epitaxial thickness uniformity is highly related to the flow field and temperature distribution on the substrate. In the actual deposition chamber, the substrate is rotating and the effect of rotation has profound influence on the thermal fluid distribution. To further understand the flow field inside reaction chamber, particle image velocimetry (PIV) will be used for flow visualization. Different inlet flow flange designs (circular holes, slots, and compound) will be tested to study the flow uniformity. Configurations of the inlet gas flow (face-down, inclined, and face-up) and exit flow will be compared to reduce flow circulation and vortex. Thermal buoyancy effect under rotating condition and experimental parameters on the flow stability issue will be studied by variation of the inlet flow rate, substrate temperature, and the rotational speed. Improvement study on the flow field inside metal organic chemical vapor deposition chamber can be achieved by the proposed research. By increasing the epitaxial thickness uniformity, it can greatly enhance Taiwan’s design and manufacturing capabilities of LED epitaxial equipment.