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

我们开发了一种用于新一代层状lsi穿透电极的绝缘子制造技术。这样的电极被计划插入基板的过孔中。孔的典型尺寸约为直径几微米，深度几十微米，比传统的大规模集成电路模式大得多。因此，必须开发新的技术来制造这种结构。在这项工作中，我们首先尝试利用真空紫外光的光化学气相沉积在孔的内表面上形成绝缘体膜。硅衬底具有相似的结构作为过孔被使用。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，在孔的内表面成功地形成了硅绝缘体膜。薄膜的厚度几乎均匀。接下来，我们尝试将此技术扩展到非汽化液体原料。一般来说，使用液体材料沉积薄膜是非常困难的，因为残留的原料很难通过厚厚的液体层从薄膜的深层去除。我们通过制造非常细的原料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。经真空紫外线照射后，我们确认胶片中只残留了微量的原料。然而，由于膜很难扩散到孔内密集的空气环境中，因此膜很难在内表面形成。认为在沉积过程中进行抽真空是获得良好填充性能的有效方法。

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.