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

我们已经开发了一种用于下一代分层系统LSI的穿透电极的绝缘体的制造技术。这种电极被设计成插入基板的通孔中。孔的典型尺寸是直径大约几微米，深度大约几十微米，这比传统的LSI图案大得多。因此，必须开发新的技术来制造这种结构。在这项工作中，首先，我们尝试通过使用真空紫外光的光化学气相沉积在孔的内表面形成绝缘膜。使用具有与通孔类似结构的硅衬底。二氧化硅薄膜形成在各种沉积条件的基板上。结果，发现在孔的内表面上成功地形成了二氧化硅绝缘膜。膜具有几乎均匀的厚度。接下来，我们尝试将该技术扩展到非蒸发液体原料。通常，由于残留的原材料难以通过厚的液体层从膜的深部除去，因此很难将液体材料用于膜沉积。我们通过将原材料制成非常细的颗粒来解决这个问题。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为数百纳米的非常细的颗粒。我们证实，在真空紫外线照射后，只有微量的原料残留在膜中。然而，膜几乎不形成在内表面上，因为它难以扩散到孔中的稠密空气中。人们认为，在沉积过程中的抽真空应该是有效的，以获得良好的填充性能。

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.