Ultra thin PoP top package using compression mold: Its warpage control

This paper will discuss how package voids Mold defect was addressed on thinner Compression mold packages like BGA (Ball Grid Array) and Sensor Devices. Significant action was the application of “Rey Resin Dispense” pattern in compression mold granule compound dispensing was a key action in reducing package voids defect. Using a DMAIC methodology (Define, Measure, Analyze, Improve and Control), a powerful analytical tool that serves as a guide towards the success of eliminating package voids defect. Using this methodology, all Key Process Input Variables (KPIVs) of compression mold and its molding compound material were identified as X’s or potential causes and test its significance to affect Y-response which is the package voids. Funneling of X’s further trimmed to the most possible contributor to package voids. The remaining possible contributor X’s undergo statistical validation which point to granule compound resin dispensing as the main contributor to induce package voids defect. Several actions were tried but failed to zero-out the defect. With the help of brainstorming and imaginative ideas and data gathered on how to improve granule resin dispense of compression mold positive outcome was realized. From the concept of light ray, to naming it as “Rey Resin Dispense” significantly reduce package voids defect in all thin BGA and Sensor devices. This learning was then applied to all existing thin packages and to new packages in compression molding process.

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A model of compression mold filling

Polymer Engineering & Science ◽

10.1002/pen.760230204 ◽

1983 ◽

Vol 23 (2) ◽

pp. 69-73 ◽

Cited By ~ 39

Author(s):

C. L. Tucker ◽

F. Folgar

Keyword(s):

Mold Filling ◽

Compression Mold

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Compression Molding for Thin PoP Top Packages

International Symposium on Microelectronics ◽

10.4071/isom-2010-wp1-paper4 ◽

2010 ◽

Vol 2010 (1) ◽

pp. 000554-000558

Author(s):

Ravikumar Adimula ◽

Jason Brand ◽

Myung Jin Yim ◽

James Zhang ◽

Richard Strode ◽

...

Keyword(s):

Material Selection ◽

Form Factors ◽

Compression Molding ◽

Mold Material ◽

Powder Form ◽

Road Maps ◽

Moire Method ◽

Pellet Form ◽

Filler Distribution ◽

Compression Mold

The package on package (PoP) has become the preferred method for vertical stacking of logic processors and memory in mobile applications. The industry is constantly working toward reducing the total stack height, and current road maps point toward a total stack Z-height of 1mm. One approach to reduce the package height is to reduce the mold cap thickness as well as reduce the mold cap clearance (the distance between the top silicon die to the mold top). In this study, we used the compression molding for manufacturing top PoP packages with 200μm, 250μm, 300μm, and 350μm mold cap and with sub-100μm mold cap clearance. As part of the mold material selection, two different form factors, granular and powder form, of the mold compound were used for the compression mold process. The key objective for this study is to investigate compression mold process and to study its effect on the package integrity. The major challenge for PoP stack up is the package warpage at reflow temperatures. All the PoP packages must meet certain critical warpage criterion to meet board mount yield requirements. Warpage of the packages was measured by the shadow moiré method, and the warpage results for the packages molded by the transfer mold were compared against that of the compression molded packages. Results indicate that there is considerable difference in warpage behavior betwee n the pellet and powder form of the same mold compound. However, the granular form of the same mold compound resulted in similar warpage behavior of the pellet form mold compound. Further analysis was done to compare the filler distribution in the mold for transfer versus the compression mold process. Results indicate much uniform filler distribution in compression mold furthering evidence that the warpage for the unit level package will be uniform across the strip. Warpage results were analyzed using finite element methods, and the results are extrapolated to different package XY dimensions. The data obtained from these experiments show that the compression mold method can be potentially implemented for thin PoP top packages in the future.

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A boundary element simulation of compression mold filling

Polymer Engineering & Science ◽

10.1002/pen.760280703 ◽

1988 ◽

Vol 28 (7) ◽

pp. 413-420 ◽

Cited By ~ 31

Author(s):

Tim A. Osswald ◽

Charles L. Tucker

Keyword(s):

Boundary Element ◽

Mold Filling ◽

Element Simulation ◽

Compression Mold

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Time-implicit fixed and deforming grid solutions for compression mold filling

Polymer Composites ◽

10.1002/pc.10629 ◽

1996 ◽

Vol 17 (3) ◽

pp. 414-422 ◽

Cited By ~ 1

Author(s):

Y. F. Chen ◽

V. R. Voller ◽

K. A. Stelson

Keyword(s):

Mold Filling ◽

Compression Mold

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Compression mold development for multiple propose applications

2010 5th International Microsystems Packaging Assembly and Circuits Technology Conference ◽

10.1109/impact.2010.5699550 ◽

2010 ◽

Author(s):

Tin-Huei Dong

Keyword(s):

Compression Mold

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The Effect of Cure Conditions on the Strength of Ebonite Rubber Network

Rubber Chemistry and Technology ◽

10.5254/1.3547909 ◽

2005 ◽

Vol 78 (4) ◽

pp. 724-735 ◽

Cited By ~ 1

Author(s):

Cattaleeya Pattamaprom ◽

Duangkamol Dechojarassri ◽

Worsak Kanok-Nukulchai

Keyword(s):

Mechanical Properties ◽

Nitrogen Atmosphere ◽

Curing Conditions ◽

Household Products ◽

Structural Applications ◽

Before And After ◽

Cure Time ◽

Long Time ◽

Compression Mold ◽

Crosslink Densities

Abstract Although ebonite has been discovered for a long time, its applications were still limited to some household products. Recently, ebonite rubber has become of interest, especially for structural applications due to its high and adjustable strength and rigidity. The rigidity can be enhanced by several folds by utilizing appropriate curing conditions. In this study, we investigate the effect of curing conditions on the mechanical properties of ebonite at various cure time. Here, the crosslink densities were determined qualitatively both before and after compression cycles to investigate the change in crosslink networks. After the pre-molding stage, the curing process was either continued in the compression mold, in the air-oven, or under nitrogen atmosphere. For the compression-mold and nitrogen-atmosphere curing, crosslink densities and the compressive moduli increased significantly with cure time, whereas, for air-oven curing, only slight increases in the afro-mentioned properties were observed. After completing four compression cycles, the crosslink density and mechanical properties remain high only when curing was done in the compression mold. Therefore, curing under pressure as in the compression mold for a prolonged time could be a mean in boosting the mechanical properties of ebonite.

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