In recent years electronic devices have become thinner, lighter, faster, and have provided higher degree of performance. This has in turn required high-density packaging of electronic components and high speed signal transfer. Use of Embedded Passives and Actives Integral Substrates are one of the technologies that are being investigated to meet the higher performance demand. We have developed a novel thermosetting resin that has a low elastic modulus, low dielectric constant and low dielectric loss. Using this material, we have developed an interlayer dielectric film that could be used for embedded passives and actives integral substrates. We have studied the property of embedding devices, interlayer connection method and substrate reliabilities. Our results indicate that it is possible to embed devices using low temperature and low pressure (150degree, 0.1MPa) with no void. In addition, we have demonstrated that the embedded devices and electrical interconnection are performed simultaneously using the prepared via opening and filling conductive paste in advance. Also, it was found that the embedded passives and actives integral substrates using the interlayer dielectric film had no warpage and other electronic components could be mounted on it. The embedded passives and actives integral substrates we demonstrated showed good reliabilities in IR reflow test and thermal cycling test. In this paper, the physical and embedding properties of the interlayer dielectric film we have developed, interlayer connecting method and substrate reliabilities will be discussed. In addition, we propose a simple manufacturing process for embedded passives and actives integral substrates using the interlayer dielectric film.