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引言 硅栅MOS大规模集成电路中,采用了多晶硅铝的多层结构,其间常用低渴淀积SiO_2膜作绝缘层。但在多晶硅条和铝连线的交叉处及开孔处,由于铝条要爬越二氧化硅膜在多晶硅条“肩”部所形成的陡峭的台阶(图1),断铝常常会发生。为了克服“肩”部断铝问题,人们进行了广泛的研究。通常采用的方法有:进一步提高铝膜厚度的均匀性。对铝膜的腐蚀由原来的湿法改为干法,以及提高低温淀积二氧化硅膜的淀积温度和增加其厚度以降低台阶高度等方法。第一种方法和第三种方法的综合使用,在4K以下的MOS RAM电路中获得了较好的效果。铝膜的干法腐蚀由于条件的限制,尚未广泛使用。然而,
Introduction Silicon gate MOS large-scale integrated circuits, using a multi-layer structure of polysilicon aluminum, during which low-thickened SiO 2 film for insulation. However, at the intersections and openings of the polysilicon and aluminum interconnects, aluminum breaks often occur as the aluminum strikes the steep steps of the silicon film at the “shoulders” of the polysilicon (Figure 1). In order to overcome the problem of broken aluminum in the shoulder, extensive research has been conducted. The commonly used methods are: to further improve the uniformity of aluminum film thickness. The corrosion of the aluminum film is changed from the original wet method to the dry method and the method of increasing the deposition temperature of the low-temperature deposited silicon dioxide film and increasing the thickness thereof to reduce the step height. The combination of the first method and the third method achieves better results in the MOS RAM circuit below 4K. Dry etching of aluminum film has not been widely used due to the limitation of conditions. however,