Optimization of ultrasonic bonding process in head stack assembly for hard disk drives | |
| Author | Dasanayake, U.D.T.P. |
| Call Number | AIT Thesis no.ISE-02-38 |
| Subject(s) | Ultrasonics Hard disks (Computer science) |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Advanced Technologies |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. ISE-02-38 |
| Abstract | Ultrasonic Bonding, a process which uses ultrasonic power together with a relatively small force to form a metallurgical bond, is one of the popular joining techniques in microelectronic interconnects. Due to the complexity of this process, the detailed mechanisms involved are still not well understood and hence there is no valid mathematical model for the process. In Head Stack Assembly of Hard Disk Drives, Ultrasonic Bonding technique is applied to join the flying leads on Head Gimbals to the bond pads on Bridge Flex Circuit attached to the actuator, in order to complete the electrical connections between the recording head and the logic board. Since the quality of the bond being an influencing factor for the performance and also for the overall reliability of Hard Disk Drives, it is with great importance to maintain the required quality of the bonds. This study was mainly focused on identifying the effects of process variables to the quality of the bonds in terms of pull strength. The general theoretical background of Ultrasonic Bonding and the specific application on Head Stack Assembly process together with the related equipments were studied. Then several sets of experiments were carried out using Ultrasonic TAB Bonding Machine and Pull Tester, to investigate the existing relation of the pull strength with power, force and time with in a selected range of each variable. Design of Experiments principles and Response surface methodology were used in experiment design and data analysis. As the result of these analyses, the ultrasonic bonding process could be approximated by a quadratic model within the selected ranges of power, time and force, which then can be used in optimization of the process. |
| Year | 2002 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. ISE-02-38 |
| Type | Thesis |
| School | School of Advanced Technologies (SAT) |
| Department | Department of Industrial Systems Engineering (DISE) |
| Academic Program/FoS | Industrial Systems Engineering (ISE) |
| Chairperson(s) | Afzulpurkar, Nitin V.; |
| Examination Committee(s) | Huynh Ngoc Phien;Lertsak Lekawat;Foster, Bob; |
| Scholarship Donor(s) | NORAD-Government of Norway; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2002 |