+---------------+------------------------------------------------------+
| **Title:**    | ## Reworkable Underfill Characterization             |
+---------------+------------------------------------------------------+
|               | **** New Proposal **** Continuing NEPP Work        |
+---------------+------------------------------------------------------+
| **Total \$    |                                                      |
| Requirement   |                                                      |
| for FY 02:**  |                                                      |
+---------------+------------------------------------------------------+
| **Technology  | **** Newly Available (COTS) **** Emerging/Advanced |
| Type:**       |                                                      |
+---------------+------------------------------------------------------+
|               |                                                      |
+---------------+------------------------------------------------------+
| **Project     | **** Parts **** Packaging **** Radiation          |
| Area:**       |                                                      |
+---------------+------------------------------------------------------+
| **Proposing   | Jet Propulsion Laboratory                            |
| Center:**     |                                                      |
+---------------+------------------------------------------------------+
| **            | **22**% GSFC **20**% LaRC                            |
| Participating |                                                      |
| Centers:**    | **53**% JPL **0.04**%MSFC                            |
+---------------+------------------------------------------------------+
| **Co          | **FY01 leveraging** was **4:1**. Contributions were  |
| llaborators** | in-kind.                                             |
|               |                                                      |
|               | A large number of industry, DoD, and Academia        |
|               | partners are already part of the current JPL SIP     |
|               | consortium. Most of this Consortium team members     |
|               | collaborated previously under JPL led BGA, microBGA, |
|               | and CSP consortia.                                   |
+---------------+------------------------------------------------------+
| **Point of    | Dr. Reza Ghaffarian                                  |
| Contact:**    |                                                      |
|               | 818-354-2059 (Tel)                                   |
|               |                                                      |
|               | 818-393-5245 (FAX)                                   |
|               |                                                      |
|               | reza.ghaffarian@jpl.nasa.gov                         |
+---------------+------------------------------------------------------+
| **In          | Dr. Reza Ghaffarian                                  |
| vestigator:** |                                                      |
+---------------+------------------------------------------------------+
| **            | -   Demonstrate a reworkable organic underfill using |
| Objectives:** |     a high I/O package and die with low rigidity     |
|               |     meeting the harsh dynamic requirements for       |
|               |     space. This task will define, characterize, and  |
|               |     validate techniques for rework and repair of     |
|               |     devices following an underfill process.          |
|               |     Evaluation will include development of           |
|               |     validation, assessment and test methods/tools,   |
|               |     advanced adhesion technology evaluation, process |
|               |     characterization and interconnect reliability    |
|               |     guidelines as they relate reworkable underfill   |
|               |     materials systems. The current standard          |
|               |     non-reworkable materials will be used as         |
|               |     control.                                         |
|               |                                                      |
|               | -   Disseminate guidelines for quality assurance and |
|               |     reliability to NASA projects for hardware and    |
|               |     processes as well as industry.                   |
+---------------+------------------------------------------------------+
| **Task        | This task meets all four objectives of NEPP program. |
| Approach to   | In this task, key properties of underfill including  |
| meeting NEPP  | bonding by mechanical and thermal test methods will  |
| Objectives:** | be characterized. Dies will be assembled on board    |
|               | with conventional and reworkable underfills and will |
|               | be subjected to environmental testing to establish   |
|               | damage progress and failure for their quality and    |
|               | reliability establishment. Non-destructive           |
|               | evaluation (NDE) and destructive physical analyses   |
|               | for reworkable underfill will be used to bound       |
|               | critical parameters and to provide                   |
|               | standards/inspection criteria for qualification and  |
|               | reliability. Guidelines for the optimum underfill    |
|               | condition for the best reliability performance will  |
|               | also be provided. Information gathered will be       |
|               | disseminated as a guidelines document. Knowledge and |
|               | experience gained will be used to effectively        |
|               | support NASA projects in these areas.                |
+---------------+------------------------------------------------------+
| **Technical   | The effect of standard non-reworkable underfill      |
| Background:** | which was characterized by the JPL-led CSP           |
|               | Consortium was the subject of a recent editorial     |
|               | article published by Electronic News                 |
|               | ([WWW.electronicnews.com)](). Several quotes were    |
|               | reported from Dr. Ghaffarian, the author of this     |
|               | proposal. The title of the article was "To underfill |
|               | or not to underfill, that is the question". Whether  |
|               | \'tis nobler to encase solder connections with       |
|               | underfill or forgo this process step is a question   |
|               | increasingly being pondered by the great thinkers in |
|               | assembly and packaging companies dealing with new    |
|               | chip-scale, flip-chip and other advanced \[package\] |
|               | technologies. Such packaging techniques are often    |
|               | threatened by thermal cycle failure or accidental    |
|               | breakage from shock and vibration, with underfill    |
|               | supposed to ward off such untimely fates.            |
|               |                                                      |
|               | In addition that underfills need to be optimized to  |
|               | achieve improvement in both thermal cycle and        |
|               | vibration for package assembly, their non            |
|               | reworkability have severely limited their wider use  |
|               | for NASA's mission that utilizes expensive circuit   |
|               | board assemblies. A number of companies that are     |
|               | currently working to develop underfills that can be  |
|               | reworked at low temperature in order to minimize     |
|               | damaging other assembled parts during defective      |
|               | package removal and replacement. At least one type   |
|               | of reworkable underfill was available at the start   |
|               | of FY00 program activity. This underfill is          |
|               | currently being evaluated to determine its           |
|               | reliability improvement under both mechanical and    |
|               | thermal environments. Promising test results on      |
|               | other reworkable underfills are currently being      |
|               | presented by other companies and a number of them    |
|               | may become commercially available in FY02 for        |
|               | evaluation and characterization. LaRC-SI developed   |
|               | by LaRC is a reworkable underfill that could be as   |
|               | sheets and will be evaluated.                        |
+---------------+------------------------------------------------------+
| **Technical   | This task will characteristics key properties of     |
| Approach:**   | underfill including bonding by mechanical and        |
|               | thermal test methods. Dies will be assembled on      |
|               | board with conventional and reworkable underfills    |
|               | and will be subjected to environmental testing to    |
|               | establish damage progress and failure. Based on      |
|               | results of non destructive evaluation (NDE) and      |
|               | destructive physical analyses (DPA), defect levels   |
|               | and their correlation to reliability will be         |
|               | established for reworkable underfills. These results |
|               | will be used to bound critical parameters and to     |
|               | provide standards/inspection criteria guidelines for |
|               | the optimum underfill condition for best reliability |
|               | performance. We will generate a guidelines document  |
|               | and will use knowledge and experience gained to      |
|               | effectively support the NASA projects in these areas |
+---------------+------------------------------------------------------+
| **NASA        | In FY00 supported ten JPL programs under RAD6K       |
| Customers:**  | activities which involved characterization of        |
|               | underfill cured under different conditions. These    |
|               | included Mars programs, MLS, SIRTF, GALEX, MIRO,     |
|               | GENESIS, and TES. Other include X-2000, STM, Mars    |
|               | Exploration Programs, MER, MLS, Europa, Deep Impact, |
|               | HPCC, at JPL, PICASSO, GAMS, STS, at LARC, Next      |
|               | Generation Telescope at GSFC. Contact: Lloyd Keith,  |
|               | Kevin Clark, John Oswald at JPL                      |
+---------------+------------------------------------------------------+
| **Milestones  | Report on the review on status of reworkable         |
| &             | underfill technology (D)                             |
| De            |                                                      |
| liverables:** | Report on assembly test vehicles with packages       |
|               | leverage through previously formed industry-wide     |
|               | chip scale package consortium (D)                    |
|               |                                                      |
|               | Release report on test matrix and environmental test |
|               | procedures for reworkable underfill test vehicle (D) |
|               |                                                      |
|               | Publish quality and reliability assurance guidelines |
|               | on assemblies with and without underfill with        |
|               | inclusion of quantifiable data (D)                   |
|               |                                                      |
|               | Report on thermal cycling to 1,000 cycles on test    |
|               | vehicles currently being thermal with reworkable and |
|               | standard underfill. Test vehicles with standard      |
|               | underfill to 4,000 thermal cycles (D, M).            |
|               |                                                      |
|               | Status report of long time thermal cycling test      |
|               | results for 5 assemblies with reworkable underfill   |
|               | and 3 with standard underfill (D).                   |
|               |                                                      |
|               | Status report on inspection, cross-section and       |
|               | quantifiable assembly data/failure data for          |
|               | reworkable underfill (D).                            |
|               |                                                      |
|               | Status report/guidelines for NASA community          |
|               | including publication in EEE links and NEPP web site |
|               | as well as papers for journal publication and        |
|               | conference proceedings (D, M)                        |
+---------------+------------------------------------------------------+
| **NASA Center | **JPL**: Organize NASA/industry-wide consortia       |
| Subtask       | activities to meet the objectives of the program at  |
| De            | the NASA centers as well as industry partners.       |
| liverables:** | Perform the majority of mechanical, thermal, and     |
|               | failure analyses to establish behavior of underfill  |
|               | and coordinate release of information gathered at    |
|               | centers and guidelines document                      |
|               |                                                      |
|               | **GSFC**: Assemble test vehicle at GSFC with known   |
|               | variables and correlation to manufacturing           |
|               | parameters and establish quality assurance controls. |
|               |                                                      |
|               | **LaRC**: Use LaRC-SI as underfill sheet for         |
|               | application prior to assembly. Characterize its      |
|               | adhesive strength and its environmental degradation. |
|               | Test materials as one reworkable option.             |
|               |                                                      |
|               | **MSFC**: Define underfill for infusion into         |
|               | missions                                             |
|               |                                                      |
|               | ### Note: The task leader                            |
|               |  will coordinate all deliverables as specified above |
|               | ; however, the subtask leaders are responsible and w |
|               | ill report their accomplishments and deliverables in |
|               |  their quarterly as required by NEPP. All subtasks,  |
|               | except MSFC, will provide inputs for the final guide |
|               | lines document to be released for NASA and industry. |
+---------------+------------------------------------------------------+

**Schedule:**

![](media/image1.wmf){width="7.875in"
height="5.322916666666667in"}**List of Procurements:**

Package/PWB/underfill

Assembly

Inspection and failure characterization

Mechanical test

**Manpower Loading:** Average Heads (FTEs)

  --------------- -------------- -------------- ------------- ------------
                  **Q1**         **Q2**         **Q3**        **Q4**

  NASA                           **.1**         **.1**        **.1**

  JPL             **.5**         **.5**         **.5**        **.5**

  Contractor                     **.5**         **.5**        **.5**

  Consultant/                                                 
  University                                                  
  --------------- -------------- -------------- ------------- ------------

+---------------+------------------------------------------------------+
|               |                                                      |
+---------------+------------------------------------------------------+
| *             | A large number of companies are currently involved   |
| *Leveraging** | that are contributing to this task. A number of      |
|               | these companies have worked under JPL led consortia  |
|               | of BGA, microBGA, and CSP and will continue to work  |
|               | with JPL under SIP. Examples are: Boeing, Raytheon,  |
|               | TRW, ITT, Litton, USAF, Harris, Sandia National      |
|               | Labs., Micron, Sun Microsystems, StorageTek,         |
|               | Celestica, Hughes Network Systems, Amkor, Kyocera,   |
|               | AMD, Sony, GE, Flip Chip. In FY00 added Lockheed     |
|               | Martin (Sunnyvale), Auburn and RIT universities to   |
|               | this team. For example, in FY00, Auburn University   |
|               | underfilled several of the test vehicles built under |
|               | microBGA consortium and is currently subjecting them |
|               | to environmental testing as in-kind contribution.    |
|               | Also, five test vehicles built under CSP consortium  |
|               | were underfilled with reworkable materials for       |
|               | comparison to standard underfill materials.          |
|               | Collaboration with other universities including RIT  |
|               | and expert industry specially chemical companies     |
|               | that are currently developing reworkable underfill   |
|               | are underway to further increase leveraging.         |
|               | Currently, we are closely working with industry      |
|               | consortia including ITRI. LARC is closely working    |
|               | with Virginia power.                                 |
|               |                                                      |
|               | **JPL**: Organize NASA/industry-wide consortia       |
|               | activities to meet the objectives of the program at  |
|               | the NASA centers as well as industry partners.       |
|               | Perform the majority of mechanical, thermal, and     |
|               | failure analyses to establish behavior of underfill  |
|               | and coordinate release of information gathered at    |
|               | centers and guidelines document                      |
|               |                                                      |
|               | **GSFC**: Assemble test vehicle at GSFC with known   |
|               | variables and correlation to manufacturing           |
|               | parameters and establish quality assurance controls. |
|               |                                                      |
|               | **LaRC**: Use LaRC-SI as underfill sheet for         |
|               | application prior to assembly. Characterize its      |
|               | adhesive strength and its environmental degradation. |
|               | Test materials as one reworkable option.             |
|               |                                                      |
|               | **Information Management and Dissemination           |
|               | Project**: Collaborate with NASA's project/mission   |
|               | assurance leaders and disseminate information as     |
|               | needed.                                              |
|               |                                                      |
|               | **NASA Training course**. Collaborate with the JPL   |
|               | and GSFC training centers to develop a training      |
|               | course for effective NASA-wide training which is     |
|               | another vehicle for information dissemination.       |
|               |                                                      |
|               | **Association Connecting Electronics Industries      |
|               | (IPC)** : Collaborate to release NASA/IPC guidelines |
|               | and inclusion in specification documents released by |
|               | IPC. Author is currently chair the IPC 9701 and will |
|               | continue to work on other specifications.            |
+---------------+------------------------------------------------------+