Development of insulator film for penetrating electrodes of layered system LSIs for the next generation

我们开发了一种用于下一代层状系统LSI电极穿透的绝缘体制造技术。这样的电极计划插入到衬底的通孔中。孔的典型尺寸直径约为几微米，深度约为几十微米，这比传统的LSI图案大得多。因此，必须开发新的技术来制作这种结构。在这项工作中，我们首先尝试通过真空紫外光的光化学气相沉积在孔的内表面形成一层绝缘膜。使用了与通孔具有相似结构的硅衬底。在不同的沉积条件下，在衬底上形成了二氧化硅薄膜。结果发现，在孔洞的内表面成功地形成了二氧化硅绝缘膜。薄膜的厚度几乎是均匀的。接下来，我们尝试将这项技术推广到非汽化液体原料。通常，使用液体材料进行薄膜沉积是非常困难的，因为残留的原料很难通过厚液层从薄膜的深层去除。我们通过将原料制成非常细小的颗粒解决了这个问题。将液体材料(硅油)溶解到溶剂(丁醇)中，并使用喷雾雾化器，成功地获得了直径约数百纳米的超细颗粒。我们证实，真空紫外光辐照后，薄膜中只剩下微量的原料。然而，由于薄膜很难扩散到孔内的稠密空气中，因此很难在内表面形成薄膜。认为沉积过程中的抽空应是获得良好充填性能的有效方法。

We have developed a fabrication technique of insulators for penetrating electrodes of layered system LSIs for the next generation. Such electrodes are planed to be inserted in the Via hole of the substrate. Typical dimension of the hole is approximately several micrometers in diameter and tens micrometers in depth, which are much larger than the conventional LSI patterns. So, new technique has to be developed for fabrication on such a structure.In this work, first, we tried to develop a insulator film into the inside surface of the hole by using a photo-chemical vapor deposition with vacuum ultraviolet light. Silicon substrates which has a similar structures as the Via hole were used. Silica films were formed on the substrates with various deposition conditions. As a result, it was found that silica insulator film had been successfully formed on the inside surface of the hole. The film had almost uniform thickness. Next, we have tried to extend this technique for non-vaporizing liquid raw materials. Generally, it is very difficult to use a liquid materials for film deposition because the residual raw material is hardly removed from the deep part of the film through the thick liquid layer. We solved this problem by making very fine particle of the raw material. Dissolving the liquid material (silicone oil) into a solvent (butanol) and using a spray atomizer, very fine particle of approximately hundreds nanometers in diameter were successfully obtained. We confirmed that only a trace amount of raw material was remained in the film after the vacuum ultraviolet irradiation. However, the film was hardly formed onto the inside surface because it was difficult to diffuse into the dense air anbient in the hole. It is considered that the evacuation during the deposition should be effective to obtain the good filling properties.