Yutaka Nomura

Large Panel Level Fan Out Package Built up Study with Film Type Encapsulation Material

Die first and face up type FO-PLP preparation was studied referring the organic substrate fabrication process. 660 mm x 515 mm size carrier was used and 640 mm x 495 mm area was encapsulated with the film molding material comparing with granule material. 3 mm x 3mm to 10 mm x 10 mm dies were mounted on the panel using temporary adhesive. Die shift at compression molding was evaluated in each die size. Larger die showed smaller die shift distance. The affection of the carrier CTE to the die shift was also investigated. The board which had CTEs of 6, 8, and 14 ppm/K were used. CTE of 14 ppm/K material showed the minimum di shift. Tracking of the warpage during the preparation process by each process step indicated that each material selection can control the warpage. Wiring layer was fabricated on the die molded panel which had the size of 510 mm x 407 mm. Laminate type insulation material was used. Filled via of 35 micron diameter and L/S = 15 / 15 micron was formed by 355 nm laser drilling and SAP.

Newly Developed Abrasive-free Copper CMP Slurry Based on Electrochemical Analysis

In order to reduce microscratches and obtain minimized dishing and erosion, we have developed new abrasive-free Cu CMP slurries. During the development of these slurries, some electrochemical examination was performed. The most effective knowledge was obtained through the analysis using rotary Cu disk electrode under pressure. On the basis of these studies, new abrasive-free Cu CMP slurries with a high removal rate and excellent planarity were designed and developed. The mechanism of reducing dishing and erosion was also discussed.

Effect of Molecular Structure of Scavengers on Copper Diffusion Deterrence in Low k Film

Low k material with high deterrence ability of copper diffusion has been proposed to reduce the effective electrical resistance of copper wirings. Providing organic low k material with deterrence ability was attempted by adding a chemical agent that chemically combines with copper. The insulation lifetime of the low k film with benzotriazole (BTA) as the copper scavenger was about two orders of magnitude higher than that of BTA-free low k film, at the practical electric field strength of 0.1 MV/cm. The copper diffusion deterrence ability was clearly dependent on the ability of the copper scavenger.

Application of embedding insulation sheet (EBIS) for FOWLP

Fan-out wafer level package (FOWLP), which is effective for thinner, lower-cost package and higher I/O, is attracting attention in accordance with the development and spread of smart phone and tablet PC. FOWLP is molded by liquid molding material using compression molding process. However, the liquid molding material has become difficult to respond to the increasing needs of large panels for cost reduction. Nowadays, the insulation material of sheet form which is capable of large size molding is attracting a lot of attention. Therefore, we have developed embedding insulation sheet (EBIS) which is capable of molding large size FOWLP. EBIS has the advantageous effect to reduce the flow distance for filling the spaces of different height and gap, compared with liquid and granular materials. EBIS is also excellent in terms of workability. In this study, we investigated the applicability of EBIS to the assembling of FOWLP. We have conducted a series of assembly process of temporary Si die bonding, compression molding, formation of photosensitive insulation material, Cu patterning by semi-additive process and solder ball mounting. Then, we have evaluated the package level warpage and reliabilities. We also conducted the adhesion and reliability tests of EBIS in combination with photosensitive insulation material (HD-8940), and found that it has the excellent adhesion and reliability of 500 h pressure cooker test.