晶圓傳送盒密封性質分析

Abstract

本論文呈現一套分析晶圓傳送盒密封墊圈密封特性之系統化流程。當閂鎖機構作動時，帶動盒門將密封墊圈下壓於盒門與盒體之間，將盒門與盒體間之縫隙密合，隔絕晶圓傳送盒內外，內部形成一密封空間，且將氮氣填充於其中，以排除內部微粒與水氣。然洩漏將於經過一段時間後發生，因此以有限元素分析密封墊圈之受力情形與其歷時變化。分析過程將密封墊圈材料之超彈性質與應力鬆弛現象納入考量，以穆尼-黎弗林模型與蒲朗尼級數描述材料受力行為進行數值分析，而此些材料模型之參數係藉由壓縮試驗配合類神經網路運算獲得。密封墊圈之密封效能將由其與盒體兩者間之接觸壓力大小評估，檢視閂鎖機構對密封墊圈之下壓狀況對接觸壓力之影響，亦考量其歷時變化情形。而晶圓傳送盒維持密封時間能以內部相對溼度評估，因此藉由菲克定律，根據閂鎖機構對密封墊圈下壓狀況，分析水氣進入晶圓傳送盒造成其密封失效之情形。最後預測閂鎖機構於相異下壓量狀況造成晶圓傳送盒維持密封之時間。

Systematic procedures are developed to investigate sealing characteristics of an elastomeric gasket of the front-opening unified pod (FOUP) used for the wafer storage in the current study. The gasket will be squeezed against a pod when a latch mechanism is operated at a lock position. Nitrogen is subsequently pressurized into the pod for the prevention of the external particle and the moisture invasion. However leakage could occur through the gasket after a certain period. A finite element analysis is carried out to explore the time-dependent response of the rubber-like gasket. Hyperelasticity with a consideration of the stress-relaxation is adopted for the gasket material. Both the Mooney-Rivlin model and the Proney series are employed in the numerical simulations. Parameters of these constitutive models are evaluated using the artificial neutral network based on experimental measurements of the gasket material subjected to a simple compression loading. Sealing performance of the gasket can be assessed according to the contact pressure of the interface between the gasket and the pod. Variations of the contact pressure over the relatively long period are demonstrated. The effect on sealing performance of the gasket under different compression by latch mechanism is then examined and compared. Sealing time FOUP maintain can be assessed according to the relative humidity inside. Fick’s law is applied to analysis the process of vapor entering the FOUP. Finally, sealing time of the gasket under different compression of the FOUP is predicted.