Please wait, while we are loading the content...
| Content Provider | IEEE Xplore Digital Library |
|---|---|
| Author | Kenny, S. Roelfs, B. Matejat, K. Magaya, T. Massey, R. |
| Copyright Year | 2010 |
| Description | Author affiliation: Atotech GmbH, Erasmusstrasse 20, 10553 Berlin, Germany (Kenny, S.; Roelfs, B.; Matejat, K.; Magaya, T.; Massey, R.) |
| Abstract | Current methods for the formation of pre-solder bumps for flip chip attachment use stencil printing techniques with an appropriate solder paste. The continuing trend towards increasing miniaturisation and the associated decrease in size of solder resist opening, SRO is causing production difficulties in particular associated with achieving sufficient yields with the stencil printing process. Practical experience of current production yields has shown that stencil printing will not be able to meet future requirements for solder bump pitch production below 0.15 mm for these applications. Also the increased costs associated with low yields are an ever present factor. This paper describes a novel approach to replace the stencil printing process by use of an electrolytic deposition of solder. In contrast to stencil printing, use of electrolytic deposition techniques allows production of solder bumps with a pitch below 0.15 mm and with a SRO below 80 jim. The electrolytic deposition of tin requires an electrical connection to each surface for metal deposition; this process is shown as made using an appropriate copper seed layer which is produced onto the structured soldermask. Specially modified activation and electroless copper processes are introduced for this critical process step. Following this the use of a photo sensitive plating resist defines the SRO which is then filled with the electrolytic tin deposit. The associated processes required both for seed layer production and for removal of plating resist and subsequent etching of the seed layer are described and first qualification results are shown from the complete process. Methods for production of electrolytic solder bumps based on pure tin as well as alloys of tin/copper are shown and in particular a method to control the alloy concentration of electroplated tin/copper bumps. Test results with both alloy system and also pure tin bumping are presented together with comparison of the advantages and disadvantages. This newly developed Sn/Cu plating process allows for a simultaneous plating of both sides of IC Substrates, the C4 and the BGA side of the panel. On the C4 side the complete Sn/Cu solder ball is plated whereas on the BGA side the basis for the subsequent placement of a larger solder ball can be achieved. Examples are given for such a process flow using the photo resist process on top of a solder resist. As a further development of the solder bumping process the photo resist free sequence is introduced which uses a modified tin deposition electrolyte to produce tin filled structures directly onto the structured and prepared soldermask. This process offers optimum solder bump plated distribution and the potential for further cost savings due to the elimination of critical processing steps associated with photo imaging. |
| Starting Page | 1 |
| Ending Page | 4 |
| File Size | 543270 |
| Page Count | 4 |
| File Format | |
| ISBN | 9781424497836 |
| ISSN | 21505942 |
| e-ISBN | 9781424497867 |
| e-ISBN | 9781424497850 |
| DOI | 10.1109/IMPACT.2010.5699485 |
| Language | English |
| Publisher | Institute of Electrical and Electronics Engineers, Inc. (IEEE) |
| Publisher Date | 2010-10-20 |
| Publisher Place | Taiwan |
| Access Restriction | Subscribed |
| Rights Holder | Institute of Electrical and Electronics Engineers, Inc. (IEEE) |
| Subject Keyword | Printing Resists Production Tin Copper Surface treatment |
| Content Type | Text |
| Resource Type | Article |
National Digital Library of India (NDLI) is a virtual repository of learning resources which is not just a repository with search/browse facilities but provides a host of services for the learner community. It is sponsored and mentored by Ministry of Education, Government of India, through its National Mission on Education through Information and Communication Technology (NMEICT). Filtered and federated searching is employed to facilitate focused searching so that learners can find the right resource with least effort and in minimum time. NDLI provides user group-specific services such as Examination Preparatory for School and College students and job aspirants. Services for Researchers and general learners are also provided. NDLI is designed to hold content of any language and provides interface support for 10 most widely used Indian languages. It is built to provide support for all academic levels including researchers and life-long learners, all disciplines, all popular forms of access devices and differently-abled learners. It is designed to enable people to learn and prepare from best practices from all over the world and to facilitate researchers to perform inter-linked exploration from multiple sources. It is developed, operated and maintained from Indian Institute of Technology Kharagpur.
Learn more about this project from here.
NDLI is a conglomeration of freely available or institutionally contributed or donated or publisher managed contents. Almost all these contents are hosted and accessed from respective sources. The responsibility for authenticity, relevance, completeness, accuracy, reliability and suitability of these contents rests with the respective organization and NDLI has no responsibility or liability for these. Every effort is made to keep the NDLI portal up and running smoothly unless there are some unavoidable technical issues.
Ministry of Education, through its National Mission on Education through Information and Communication Technology (NMEICT), has sponsored and funded the National Digital Library of India (NDLI) project.
| Sl. | Authority | Responsibilities | Communication Details |
|---|---|---|---|
| 1 | Ministry of Education (GoI), Department of Higher Education |
Sanctioning Authority | https://www.education.gov.in/ict-initiatives |
| 2 | Indian Institute of Technology Kharagpur | Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project | https://www.iitkgp.ac.in |
| 3 | National Digital Library of India Office, Indian Institute of Technology Kharagpur | The administrative and infrastructural headquarters of the project | Dr. B. Sutradhar bsutra@ndl.gov.in |
| 4 | Project PI / Joint PI | Principal Investigator and Joint Principal Investigators of the project |
Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon |
| 5 | Website/Portal (Helpdesk) | Queries regarding NDLI and its services | support@ndl.gov.in |
| 6 | Contents and Copyright Issues | Queries related to content curation and copyright issues | content@ndl.gov.in |
| 7 | National Digital Library of India Club (NDLI Club) | Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach | clubsupport@ndl.gov.in |
| 8 | Digital Preservation Centre (DPC) | Assistance with digitizing and archiving copyright-free printed books | dpc@ndl.gov.in |
| 9 | IDR Setup or Support | Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops | idr@ndl.gov.in |
|
Loading...
|