改善因應力所引起之異向磁阻感測器 可靠度失效之研究報告

Abstract

當莫爾定律到了盡頭，工業4.0智能產業隨之興起，因此感測器的發展是物聯網最重要的應用，文中以三軸單晶片的異向磁阻感測器為主，說明其於量產後面臨需維持可靠度穩定性的挑戰及相關的改善方法. 異向磁阻感測器具有薄膜疊層簡單的特性，但其應用於三軸立體方位感測時，其立體的結構形狀更易於解析磁特性的變化，也相對的容易引起應力的變形，因而造成可靠度的失效，為改善此問題，於本文中將採用調整特殊邏輯積體電路與感測器之介電層與金屬層應力的手法，將其應力釋放以改善磁特性於可靠度驗証的穩定性. 三軸單晶片異向磁阻感測器的設計是需由特殊邏輯積體電路與感測器垂直整合而成，技術困難在如何能穩定良率於生產製造的部份, 但其最大的挑戰會在於產品可靠度驗証，但若能解決此問題，其磁阻感測器將可應用於電子消費性用品，穿戴式裝置、車用甚至可達到工業用產品的規格，也將能達到多方廣泛的產品應用層面.

When the Moore’s Law goes to the limit, “Industry 4.0” intelligent industry will raise. The development of sensors is the most important application of IoT(Internet of Things). Single-chip three-axis Anisotropic Magneto-Resistive (AMR) sensor technology requires the integration of the ASIC (Application-Specific Integrated Circuit) with sensor itself. To have stable yields for production, its biggest challenge will be the reliability verification. This paper proposes a possible solution for the improvement of reliability and stability of the single-chip three-axis AMR sensor. An AMR sensor is constructed by a simple film stack where its 3D trench stack pattern is very sensitive to magnetic response. However, the drawback is that the flexible structure tends to lose the reliability during deformation. In order to circumvent this problem, metal-adjusted sensor and dielectric-adjusted ASIC for stress relief were both employed. We find this approach is able to release the stress and meanwhile improve the AMR sensor‘s reliability. The proposed method may open opportunities for the AMR sensors to be used in 3C consumer wearable product and even automobile industry.